diff --git a/2021/10/README.md b/2021/10/README.md
new file mode 100644
index 0000000..85ff953
--- /dev/null
+++ b/2021/10/README.md
@@ -0,0 +1,11 @@
+# 10
+
+Description
+
+<details>
+  <summary>Solutions</summary>
+  <ol>
+    <li>392097</li>
+    <li>2</li>
+  </ol>
+</details>
diff --git a/2021/10/input.txt b/2021/10/input.txt
new file mode 100644
index 0000000..e7230b6
--- /dev/null
+++ b/2021/10/input.txt
@@ -0,0 +1,111 @@
+([[<[[[[<{((([<>][{}<>])[<<>{}>[{}[]]])((({}())({}{}))<<()<>>([]<>)]))<<[[[][]][{}[]]]>[([(){}]((){})){<<>
+[(<[<<<{([(<{(<>())}(({}[])<<><>>)>)]){{[<[[<><>]{{}<>}]>[[<()[]>((){})]]]}[<({<<>{}>{[]<>}}(({}())[<><>]))
+<<(<<[<{(({[({{}<>})<({}<>)<()[]>>]})<[(<{[]}<{}{}>>)(<{{}()}[<>[]]>)](<<<[]><(){}>>>{{{<>[]}([
+([[{[{<{{(([<([]{})[[]{}]>][<({}())[{}()]>{<[]{}><{}[]>}]))<([(({}<>))])>}}>}<<[<{[<<({}[]]([]{})>>]}><{
+<({[<({(({{[(<[]()>{{}{}})][<[{}{}]{()<>}>[<()()>]]}}){((<<{[]<>}>(({}<>){[]<>}>>(<[<>[]]{<>}><{[][]}[<><>]>
+[(<({([{{{{{([(){}][<><>]){[(){}]{{}<>}}}((<{}{}>(()[]))[<{}()><[]()>])}{<({{}()}<<>{}])[{{}{}}{[]<>}
+({<<{{{{(((<({<>()})({{}}{{}{}})>{{([]{})<<>{}>}{<[]{}>{()[]}}}){[<[<>[]}[[][]]>{[{}[]]<<>()>}]<{({}<>)<{}
+[({{<<[{<({[<<{}{}>([][])><{(){}}>]{[[[]<>]][(<>()){{}}]}})(<[<{{}()}<<>[]>>([{}]{()<>})]>)>}[(<[({[<>[]]([]
+({[([(<([[<(({[]{}}{[]{}})<{()()}{<>()>>)[<{{}<>}>({[][]}(<>[]))]>]{(<{{[]{}}[[][]]}[[()[]][
+{([<{<{([<[[[[{}()]]]{<{[]()}((){})><[[]]<<>>>}][<<<{}<>>{()<>}>{<{}()>[{}[]]}>[(([]<>))[<[]{}>[[]]]]]>]<[
+<{[{{([[(<<<{({}{})(()<>)}[<{}()><{}<>>]>>>(<{{[{}()][(){}]}([[]()]([]<>))}{{<{}[]>{{}[]}}{[[]{}]{()
+{<{[<([{([[{{(<>[])[<>[]]}}][(<{[]()}<{}{}>>{<<>()>((){})])[{[<><>](()<>)}<<{}{}><<>[]>>]]])}])
+<[[[{<[<([[({[<>[]][()<>]}(({}[]){[]<>}))]])[([<<([])><<()[]>{<>[]}>><([()()]<[]()>){<<>[]><[]<>>}>]({<({}[]
+((<{{{[(({[[([()[]]([][]))(<[]<>>([]()))](((()())([]<>)){(()[])([]<>)})][{<([]{})<[][]>>{<[]{}>{(){}}
+(({{<[[{((((<<{}()>[()<>]>){[(()<>)([]())]})<{[<{}()>[[]()]]}<((<>())({}{}))[({}{}){{}<>}]>>))<[(({<
+[<{[{{({<[{[(<[]{}>{(){}})({{}<>}{{}{}})]<([[][]][[][]])((<><>)<<>()))>}<({{{}()}{{}{}}}(<[]{}>{()
+{{{{[{[{{<[[[{()<>}(<>[])]<{{}[]}[[][]]>]<<<<>>>>]{[[{()<>}<[]{}>]{{{}{})[{}[]]}]<(([]<>){{}()})>}>}[<([[({}
+([<<(({(<{{{<{()<>}>}}{(<({}<>){[]{}}>[<<><>><()()>])}}(<(({<>()}<(){}>){(<>{})[<>()]})>[(({<>[]}
+<{([[<{(((<(<[{}{}][(){}]>{<{}<>><[]<>>})<((<>())<()[]>)(<{}()>[[]<>])>>[(<[[]{}][[]()]>[<()()>[{}<>]]
+<[{{(<{[<(<[{[[][]]<()<>>)<(()<>)[<>()]>][<{{}{}}(<>[])>(<()[]>(()()))]>)<{<[{[]{}}]>[{<[]<>><<>{}>}]}[<{<
+[{((({({[<[<[(<>()){()[]}]([<>{}]{<>{}})>{[[[]<>][[][]]]{(()())[<>[]]}}]{{{{<>[]}{{}()}][([]
+<[{[<{(<((<{<{[]{}}(()<>)><(()<>){(){}}>}[{[{}[]]}<(()())[()()]>]>{{[<()[]>]{(<>[])<()()>}
+{<([<([{{{(({{()[]}}[([][]){(){}}]))}[[{{(<><>)<<>>}<<()()>>}][{[[[]<>]{(){}}]}<{{[]<>}<{}[]>}{{<>[]}<
+<<[<{{[<[<<([[{}<>]{[][]}][[{}{}](()<>)])[([{}]({}{}))[([]<>)<<>[]>]])<[<[()<>]>{[[]{}]<{}{
+[{[{<[({<((<[<<><>>(()<>)](<{}[]><<>()>)>[{([]())[()<>]}])([<([][])<()<>>>([<><>])]))[[{({<>[]}[()[]])}[[{(){
+{[([[<{[<{<{[(<>[])<{}()>](((){})([]<>))}[({<>[]}[()[]])([[]<>][{}{}])]><{{<()()>[()]}(<[]<>>[{}<>])
+{[<([(({([<[([()[]]<[]{}>){<{}<>>(()<>>}]([(()<>)([]())]((<><>)({}())))>]){[{(<[[]{}][(){}]>({[]{}
+[({<[{[<({<((<<><>>){[{}()]})<<{{}{}}[[]()]>(({}()))>>{[[{{}<>}({}<>)][(()<>)({}{})]]<{[()<>
+[([<{<{<{[(<[((){})[<>[]]]{{{}<>}[{}[]]}><[[()()][()()]]>)([[{[][]}{[]()}]]({<[]<>>(()<>)}[[[]<>]({}<>)]))
+<([<{[<<[<(<{{(){}}({}{})}[<<>()>(<>())]>[<<[][]>([]())>{[<><>]<{}()>}])>]{{[{[<{}{}>(<>{})][[<>()]<<>[]
+<{([<<(<{{[{<[(){}]{[]}>((<>[]){()[]})}(<{<>}(()())>(<<>[]><<><>>))]<[<<[][]>([])>]>}}{[<<(<[]>{<>[]])(<()<>>
+(<{([<{[(<<(<[(){}]({}())><{()[]}<[]()>>){[<<><>>[{}[]]]<({}<>)[[]<>]>}>{[[([]{})<{}[]>]][{<[]
+<<({[<({<{[((({}))<(<>[])>)<[[<><>]([]())]>]}<{[<{(){}}(()())><<[]<>>{()[]}>]}>>[<{{{<()()>[[]()]}(<
+[{[{<{[[{{{[<[(){}]{<><>}>(({}[]))]}<(<[[]<>]{<><>}>{(()){(){}}}>[({()()}<{}[]>)]>}}]{<((<{<(){}><{}<>>}
+{([((<<([{<[[([][])<{}[]>][[(){}]{[]<>}]](<{[]{}}<<><>>>)>[{{{<>{}}([]{})}[<[]()>(()())]}{<(<
+<{{((<{{({{<(<(){}>({}<>))[[{}[]]{[]{}}]>{[{(){}}{()[]}]({<>[]}<[][]>)}}([(<(){}>[[]<>])[[{}{}]<{}<>>]
+[<[<({[<{{{{{<<>[]>}({<>()})}}([[(()<>)<()()>]]>}([(((<>{}))[[<>[]][()[]]])<{([]{})(()[])}>]<{
+<<[<{<{({<([({{}[]}){{{}()}{{}{}}}]<[{()()}<<><>>]{(<>())(()())}>)(<{({}<>)([]{})}(<<>{}><[]()>)>{
+([{({{<<<{{{((()[])(<>[])){(()[])[()<>]}}(((<>{})<()()>))}<<[{<>{}}{{}[]}]<(<><>){<>[]}>>(<{<>[]}<(){}>>)>
+{[[(<({{[<<([<()[]>[(){}])<<[][]>[<><>]>)({({}())([]{})}[{{}()}({})])><<{{[][]}[()[]]}{{{}()}{<>[]}}
+<(<[{<<{[{<({{()<>}[{}[]]}[<{}>({}<>)])<[{(){}}(<><>))>>[<{<[]{}>[{}()]}<[()]<<><>>>><{<{}{}>[[]<>]}[<()[]>(
+<([{{{([<(<(<[()()]{[]()}>{[()()]{{}{}}}){[[[]<>]{[]{}}]<<()<>>>}>)[[{(({}<>)<<><>>)[[()()]{[]()}]}(<[(){}]{<
+{[<{{<(<{<<[<(<>())({}())>[[()]{[]()}]]({{[]()}}<<[][]>{<>{}}>)>>(([[[{}[]]((){})]([[]{}]{
+<<<<(<{{<((<[<()()>{<>[]}]>)[[<({}())<(){}>>]{(<(){}><<>()>)[{<>[]}[{}<>]]}])(([<<<>{}>>[{[][]}{{}{}}]]{<[
+([[<<<({[[(<([<><>]{<>()})>(([<>][{}<>])<[[][]>([]{})>))({{<[]>{<>()}}{<[][]>[[]{}]}}<[{[]{}}{{}{}}
+{[[<<(<<([(([{<>()}<<>()>]{[{}[]]{()[]}}){[[(){}){(){}}]{<<>[]>{[]<>}}})[<([[]]<<>{}>)>{{{<>{}}<<><>>}[[
+(<{{<([[[([[(<()()>[[]<>]){[{}]{[][]}>]])[<[{(<>)(()[])}({<>[]}[{}()])]{<[<>{}]{{}()}>{{()}{<>{}}}}>([
+{<[{(((([<[{{<<>()>[()()]}<([]())<[]()>>}<((<>))[<[]{}>{[]<>}]>){{([()]<<>[]>)[<[][]>{()}]}[{((){})
+((<{<{<(((<(({(){}}([][])){((){})<[]>})({(()[])(()())}{{()<>}[<>{}]})>[(<[()]<[]{}>>(([][]){<><>
+{{{({[{(<<<<[[(){}]<<><>>]([[]{}]<{}[]>)>>>>[{{<[{<><>})[(<>[])[{}{}]]>{{<<><>>}({<><>}{()()})
+{{[{[(({[(({<[{}{}]>[{[]<>}[{}()]]}(((()<>)<()[]>))){{{<{}[]>{{}<>}}{{{}<>}}}<<<{}{}>>(({}()))>})({<<{
+{<{<[<(<{<[(<({}{})[[]{}]>{([]<>)[<>[]]})>([<{<>()}{[][]}><{()[]}<[][]>>][<{{}{}}{[]()}>[<<><>>[{}<>]]]
+{({{[<(<[[<[[({}{}){<><>}]](({()<>}{{}<>}){({}<>)<()[]>})>]}><<<{{(({}{})<()()>)([{}[]][<>[]])}
+(<<{<<{{[{((({[]{}}))<([<>()]{{}{}})(<{}{}><[]<>>)>)[{({{}{}}<()>)}([<{}[]>([]())]{<<>[]}([]{})})]}<
+{{<{([[<[(<[[<{}<>>]({[][]}<<>{}>)][[[()<>][<>[]]]{[[][]]}]>(({([])[<><>]}[(()<>)<(){}>])<<[{}]{<
+<{{{[<{[<<[<{[<><>]{[]{}}}[<{}()>{{}[]}]><<<[][]>{{}()}><(<>())[<>[]]>>]<[[<()[]>[<>[]]](({}<>))]>>]]}>]{([<(
+[<{({{[{<<{<<[()<>]<<>()>>([<>[]]([]()))><[<<>{}>{{}{}}]>}(<{[()()][()()]}(([]{}))>)>([(({{}()}<[]{}
+(<{{({({({<<((()<>)(()()))[(<>[]){<>[]}]>({({}[])[<>{}]})>})}){[[({{(<()<>>{<><>})<{<>[]}<{
+[[<<<{<<[<[[{<{}{}>(<>{})}]{([[][]][[]{}])<([]<>)<[]{}>>]]>[[<[[()[]]({}())](([]())[()<>])>
+{[(<[[{({<{<[{(){}}]{[[][]]<()[]>}>}}[([<[{}[]]([][])><<[]()>[()()]>]({<()<>>(<>[])}<<(){}><<><>>>)
+[{(<<{{[<{{{[[(){}]({}())]<(<>[])>}<{{()<>}(<><>)}>}}[(((([]())[(){}])(({}<>)<()()>))[<(<><>)<[]{}>>
+<<<{<([[[({{<([]{})[{}()]>[([]<>)[[]()]]}(<<<><>>>)}[[{<()[]>({}<>)>]([[<><>]][(())[[]()]]
+([{{([<<<{{(<[{}[]][{}()]><[<>()]{[]()}>)({{[]<>}[{}()]>({()<>}<{}()>))}[<<<{}<>>{[]()}>>]}>>>
+{[<{{<{{<[[<({()[]}{<>{}}){{<>[]}{(){}}}>]]<([[[[]{}]{{}{}}][<{}()><[]{})]])({((<><>)[()[]])<[[]]<{}<>>>}[
+[[{(<<{<{<{<((<><>)[<><>])>}>({<(<[]()>[(){}>)>{{[[][]]}{{()()}{()()}}}})}{[{{((()())((){}))(({}
+[{[<{[((<<[(<<<>[]>({}[])>(<<>>{<>[]})){{({}())[{}<>]}{{<><>}{<><>}}}][[{({}<>)}({<>()}[(){}])]
+<<([[{([{{<<<<{}()>({}())>([()()])>(<([][])><<()[]>>)>}}{<{[<[<>{}][<><>]>]<[(()())[()<>]]<{{}{}}{[]<
+{{[<{{[{{{<{<<<>[]><()<>>>(<{}<>><{}{}>)}<[((){})[[]{}]]{<{}>}>>}<[[([{}[]]{[]<>})][([()<>]<{}
+[(([(((<{[{{<[[][]](<>{})><{{}[]}[(){}]>}{(({}[])([][]))<[{}[]][[]]>}}([[{[]}(()[])][([]<>){()
+{[<{<<[<{([<({[]<>}[()]){[[]()]([]())}>{([<>]{<>{}})}])<(([({}[]){[]<>}]{([]<>)[[]<>]}){{<(){}}[{}[]]}([[]{
+[{<<<[<[{(<{({{}{}}[[]()])([[]()])}>)[[(({<>}({}())){{<>[]}<[]<>>})[(<<>{}>)]]]}{<[[[[{}()}(<>())]{<<><>
+((([{[<({([[((<><>)[{}()])(({}<>)({}()))]{[<<>{}><<>()>]({()()}[<>])}]<[{[{}()]}([{}{}]<()()>)]>)}<([<[{[]
+(<[<{[<[{[[<[<{}()>[[]]]>{{<<>>({}[])}<{{}<>}>}][({<()()>[()[]]>({[]()}))]]}]({<({<[{}()]{{}()}>{[()<
+(<<([{<[<(<[[{[][]}[(){}]]]}<{{<{}{}>}{(()[])(()())}}>)>][[{[([([][])(<>())](<()>[[]()]))(<{[]()}{()
+[{{<<<<{(({{({{}[]}<()[]>)({{}()}{<>()})}<[(<>())]{(<><>)}>}((([<>()]{{}[]})[<<>[]>(()[])])[(<{
+<[[{<([[<[{(({<>[]}({}()))(<[]<>>{<><>}))<[(<>[])(()<>)]{{(){}}{{}<>}}>}([[{()()}(()())]]((<[][]>([]()))(<
+(<(<[{<([[({<<(){}>[{}()]>[<[]>[()()]]}(<<{}{}><[]<>>>({{}[]})))<[({[]()}[{}<>])<(()<>){[][]}>]{([
+{(<(((<[<<<[[(()())[{}]]({<>()}({}()))]<<{()()}(()())>[{<>[]}[[]<>]]>>>([{(<{}{}>{{}})<[{}[]](<><>)>)[<[<>
+<[<([<{<<<{{{<()[]>{<>[]}}[<[][]>[{}()]]}}<{{{[]<>}<[]{}>}<{{}()}[()()]>}>>)>[([<{((<>{})[()(
+<<[<<{([[[[<[([][])((){})][{{}()}({})]>([{{}{}}(<>[])])]{{(<<>[]>{()[]}){[<>()]{[][]}}}[{{<>}<{}<>>}<<{}()>((
+{{(<{[<<[{[(<<[]>(<><>)>[{[]()}{<>{}}))<{({}[])<[]{}>}{(<>{})[[][]]}>]<(([<>{}]([][]))<[[][]][<>
+(({([{({<[<<{([]())(<>())}([<>{}])><({<>})<<<><>>>>>[<{[{}<>]{[][]}}<{()()}<[]{}>>>[{<()<>>{{}}}
+<{[{({[(({[((<()>{()<>}))<([()[]]<<>()>)[{(){}}([])]>](({<()[]><{}<>>}({{}}([][]))))}))<<[[[[{(
+[{<([[({{{{({([][])[<>{}]})[{({}{}){<>{}}}]}({[{[]{}}([])]({()()}<[]{}>)}<[[{}{}][{}[]]]{<(){}>{<><
+(<[{{{{[{(((<[[]())([]())>{<()()><[][]>})){<(<<>{}>[[]()]){{<>{}}[<><>]}>[<{<>()}<{}{}>>{<()[]
+({{[{[[[{<{([<{}<>>[{}()]])(({()[]}{()[]}){<{}<>>{()}})}<<{[<><>]}<[()[]>{{}<>}>><((()[]))>>>
+{<[(<{[(([({<[<>[]]<<><>>}[[<>()]{{}<>}]}[{<{}>}<[()<>]<[]()>>])(<[[<>()]{{}()}]<({}[])[{}()]>>([[<>{}]<<
+{<[<{{(([{[[{<[][]>[<>[]]}<[{}<>]<<>{}>>]]{<(([]<>))((<>{})[<>{}])>{(<{}<>>[<>])([(){}]{<><>})}}}[{[({{}<>
+<<({[(<{<[{{[<{}[]>]<[<>{}]{[]<>}>}}<([{[]<>}]{(<>{})}){(<[]<>><()>)[<()()>([]{})]}>](([{{[][]}[{}[]]}[{<>[
+[<[[[[<({([[[[<>()]{{}()}][{<>{}}{[]}]]<{<{}>{<>)}>]{[<[<><>]{()()}><((){})(()())>]{(({}[])){[()()](
+{<[[[<<<<<{[<[<><>]<()<>>>{{()[]}[{}()]}]<<[<><>]{()()}>>}({{{<>()}([]<>)}[[(){}][()[]]]})>>>>>]
+(<[{{[[{({[{<{<>[]}[<>[]]>}]})}{{({{{([][])((){})}(({}[]))}([{<><>}(()[])]({<>{}}<{}>))}{([((
+<[[(<{({<<{{[{<><>}]<(<>{})<<>()>>}[<([]<>)(<>[])>[<{}<>><[]<>>]]}<({{{}<>}[()<>]}{[<>[]][[]
+{{<[[<<<{{{(<[{}()]>[<(){}}(()[])])[[{(){}}<{}()>][({}[])([]{})]]}}[<<<[()()]{[][]}><<[]>>>{<<{}[]>{<>[]}>[<
+((<<{([[([[<([[]{}]<[]{}>)>]](<({{{}{}}([][])}{(<>())[<><>]})[((()())[{}{}])[(<>{})[[]<>]]]>))[{{({{{}{}}[<
+<<<(<(<[[<(<[{()[]}<{}{}>]>([{[]()}[()[]]]<(<>())>))[{({<>{}><{}<>>)}{[[{}()](())]<<()[]><<><>>>}]>{{<(
+{{{<(({{[(({{<[]()><<>>}{[()[]]{<>{}}}})({<<()]<[]{}>>}([[()()]{[]<>}]))){<(<(<>()){[]<>}>[
+[({([{<(<[<{[<<>[]>[[]]]{[{}[]]<(){}>}}{<<[]()>({}())>([[]{}][[]()])]>]<<{{[{}{}][[]{}]}{{(){}
+<{{<[[([[(<{{{<>[]}[()<>]}(<[]{}>)}<{[{}{}]({}{})}>><{[{{}[]}(<>{})]<{<><>}<{}{}>>}>)][<{({[(){})<()()>})
+<<{{[{{[[{{[({{}[]}[()[]])({[]<>}{{}()})](<<<>[]>{[]<>}>{{()[]}[<>()]})}}](<{{{<<><>><{}[]>}}}({
+[<[<<(<[((((<(<>[]}<[]>><{[][]}({}{})>))[<{[[][]]}([{}<>][{}])>[<{[]()}({}{})>{(()()){{}{}
+[<<{[([[([{<[{(){}}[{}{}]]><{[[]<>][(){}]}<{[]{}}[()()]>>}({((<>))<{()}<[]{}>>}{[[[]]{<><>}]<[[]<>]
+[[[{<([{[<[<{[<>()]<()<>>}<{<>()}<[]<>>>>([(<>{})(<>[])]<<(){}><[]<>>>)]({{[<>{}]}({<>[]}<()[]>)}[(<{}<
+{<<[[{([{((({[{}()]{()[]}}[<{}>[{}{}]]))({[<(){}><()[]>]}))}])[<(<([([<>{}))<[[][]]{(){}}>])(
+[{(<<{<[[{<[{[{}[]](()<>)}[[{}{}][[]<>]]]><(<(<>[])({}())>[{{}{}}<<>()>>)>}<{(<<{}[]>[[]()]>{<
+<{(((([<{[{[<<(){}>[()<>]>{<{}>({}())}]{[{<>()]({}{})]}}][(<<{()()}>({[][]}<{}[]>)>)]}[(<[{(
+([<((<<[([[[<[()()]<{}()>>]<(<()()>[[]])[<{}<>>((){})]>}{({((){}){[]{}}}[[[]]<{}<>>])(<{()[]}[()[
+{((<[({<<({(<{<>[]}{[][]}>){<<()()>{[][]}><{[]{}}>}}<<[<[]>(<>())]<<<>{}>{{}()}>>[[[<>{}]<()()}]<
+[[<{{{({([((<[()<>]<{}>><(()[])[{}()]>)[({<><>}({}))<<{}<>><[]{}>>]){[([{}<>](()()))]<[{()
+{<<[[{[[[[[[[[<>()][{}]]<(<>())(()[])>]]<{[<[]<>>({}{})]}<[({}())][{{}()}{{}[]}]>>]<[[(<()()>{[]{}})
+
diff --git a/2021/10/python/main.py b/2021/10/python/main.py
new file mode 100644
index 0000000..ea85413
--- /dev/null
+++ b/2021/10/python/main.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+
+from os.path import join, dirname
+from typing import List
+
+# Day 10
+
+# Common
+
+
+def read_input(filename):
+    data = join(dirname(__file__), '..', filename)
+    with open(data) as f:
+        return f.read().strip()
+
+
+test = read_input('test.txt')
+data = read_input('input.txt')
+
+
+class Node:
+    def __init__(self, brackets, children):
+        self.brackets = brackets
+        self.children = children
+
+    def add_child(self, child):
+        self.children.append(child)
+
+    def __repr__(self) -> str:
+        return f'{self.brackets} -> {len(self.children)} {self.children}'
+
+
+class Parser:
+    openers = ['(', '[', '{', '<']
+    closers = [')', ']', '}', '>']
+
+    def __init__(self, code: str):
+        self.tollerant = False
+        self.code = code
+        self.pos = 0
+        self.valid = True
+        self.nodes: List[Node] = []
+
+    def parse(self, tollerant=False):
+        self.tollerant = tollerant
+        root = Node(None, [])
+        try:
+            self.traverse(root)
+        except Exception as e:
+            # print(e.args[0])
+            pass
+        self.nodes.append(root)
+
+    def traverse(self, node):
+        c = self.code[self.pos]
+        typ = self.openers.index(c) if c in self.openers else -1
+        if typ == -1:
+            self.valid = False
+            raise Exception(
+                f'Invalid character at position {self.pos}. Found {c}')
+
+        node = Node(typ, [])
+        while True:
+            self.pos += 1
+            closing = self.closers[typ]
+            if self.pos >= len(self.code):
+                if self.tollerant:
+                    self.code += closing
+                    break
+                else:
+                    raise Exception("EOF")
+            c = self.code[self.pos]
+            if c == closing:
+                break
+            else:
+                node.add_child(self.traverse(node))
+        return node
+
+
+class Checker:
+    def __init__(self, lines: List[str]):
+        self.lines = [Parser(line) for line in lines]
+
+    def flag1(self):
+        for line in self.lines:
+            line.parse(tollerant=False)
+        points = {')': 3, ']': 57, '}': 1197, '>': 25137}
+        flag = [
+            points[line.code[line.pos]]
+            for line in self.lines
+            if not line.valid
+        ]
+        return sum(flag)
+
+    def flag2(self):
+        added = ''
+        for line in self.lines:
+            print(f'\nChecking:')
+            print(line.code)
+            before = len(line.code)
+            line.parse(tollerant=True)
+            if line.valid:
+                print(line.code)
+                added += line.code[before:]
+
+    @ staticmethod
+    def parse(lines: str):
+        return Checker(lines.split('\n'))
+
+
+# 1
+print('1.')
+checker = Checker.parse(test)
+print(f'Test: {checker.flag1()}')
+checker = Checker.parse(data)
+print(f'Real: {checker.flag1()}')
+
+# 2
+print('\n2.')
+
+checker = Checker.parse(test)
+print(f'Test: {checker.flag2()}')
diff --git a/2021/10/test.txt b/2021/10/test.txt
new file mode 100644
index 0000000..b1518d9
--- /dev/null
+++ b/2021/10/test.txt
@@ -0,0 +1,10 @@
+[({(<(())[]>[[{[]{<()<>>
+[(()[<>])]({[<{<<[]>>(
+{([(<{}[<>[]}>{[]{[(<()>
+(((({<>}<{<{<>}{[]{[]{}
+[[<[([]))<([[{}[[()]]]
+[{[{({}]{}}([{[{{{}}([]
+{<[[]]>}<{[{[{[]{()[[[]
+[<(<(<(<{}))><([]([]()
+<{([([[(<>()){}]>(<<{{
+<{([{{}}[<[[[<>{}]]]>[]]