diff --git a/2021/src/main/kotlin/Day10.kt b/2021/src/main/kotlin/Day10.kt
new file mode 100644
index 0000000..87cafb0
--- /dev/null
+++ b/2021/src/main/kotlin/Day10.kt
@@ -0,0 +1,61 @@
+package be.vandewalleh.aoc.days
+
+import be.vandewalleh.aoc.utils.BaseDay
+import be.vandewalleh.aoc.utils.input.Day
+
+@Day
+class Day10 : BaseDay() {
+    private val chunks = mapOf(
+        ')' to '(',
+        ']' to '[',
+        '>' to '<',
+        '}' to '{',
+    )
+
+    override fun part1(): Any {
+        val points = mapOf(
+            ')' to 3,
+            ']' to 57,
+            '}' to 1197,
+            '>' to 25137,
+        )
+        return input.lines.value.sumOf { line ->
+            val stack = mutableListOf<Char>()
+            for (char in line) {
+                if (char in chunks) {
+                    if (stack.last() == chunks[char]!!) stack.removeLast()
+                    else return@sumOf points[char]!!
+                } else {
+                    stack.add(char)
+                }
+            }
+            0
+        }
+    }
+
+    override fun part2(): Any {
+        val points = mapOf(
+            '(' to 1,
+            '[' to 2,
+            '{' to 3,
+            '<' to 4,
+        )
+        return input.lines.value.mapNotNull { line ->
+            val stack = mutableListOf<Char>()
+            for (char in line) {
+                if (char in chunks) {
+                    if (stack.last() == chunks[char]!!) stack.removeLast()
+                    else return@mapNotNull null
+                } else {
+                    stack.add(char)
+                }
+            }
+            var score = 0L
+            stack.asReversed().forEach {
+                score *= 5
+                score += points[it]!!
+            }
+            score
+        }.sorted().let { it[it.size / 2] }
+    }
+}
diff --git a/2021/src/main/resources/day10.txt b/2021/src/main/resources/day10.txt
new file mode 100644
index 0000000..661c46a
--- /dev/null
+++ b/2021/src/main/resources/day10.txt
@@ -0,0 +1,94 @@
+{[<([<[[(<[({<<><>><()[]>}<(()())(())>)<(([]())){<()()><{}<>)}>][(((()<>)[{}{}]){<[]<>>({}{})})]>)[(({([{}[]]
+{{[[(<[[[<[<<{()()}(<>{})>[<<><>>[[]]]>[{{[]<>}[[]]}<<[]{}>[<>[]]>]]([[[{}<>]]<<()[]>{()<>}>]([<<
+([<{[[{{((([(<[]<>>{[]<>})<([]){<>{}}>][([<>[]][[]{}])])[[{{()[]}<()[]>}<{(){}}>]]]<{(<[{}<
+(({(<{(([<[({([]())(<>())}{([]{})[{}{}]})]{(({{}()}{<>()}](<[]<>>(()[])))({[[]{}]<[]<>>})}>[[[{<<>[]>(()
+[([<([{({{[{[([]{})[{}[]]][[{}{})]}<([<>{}]<<>()>)>]}([<{[()<>]{()<>}}[[{}{}]<(){}>]><{{{}[]}[()<>]}[{{
+<(([<{{<(<[(<{()()}>(({}()){()[]}))<[<[]()>[[]()]]<{[]()}<<>{}>>>](<[([]())]>(([()()][()<>])({()<>}<[]<>>))
+[{({<(<[{({{{[()[]](<>[])}{([]{})<<>{}>}}}{{<<{}[]>(<>)><(<><>)([]())>}<{({}<>)(<><>)}{[{}{}
+([(<{<[<{[({[<[]{}><<><>>]<({}[])({}<>)>}([{{}<>}<[]()>]<<<><>>>)){({<<><>>[[]{}]}(<()<>>{()}))<{<[
+({{([(<{{{{{{([]{}){<>{}}}}{<<()>{{}{}}>[({}())(()<>)]}}[[[[{}{}](<><>)]{<()[]><[][]>}](([[]](()()))<[[]
+(<<[<{{{({{<{{(){}}{<>()}}<({}{}){[][]}>>[{<[]{}>{<>()}}<{[]<>}[()<>]>]}}({([({}[])(<>{})][{<>}])[{[()<>]<{}
+{[(<<((<[[<{<{<>()}[{}[]]>}{{((){})[()<>]}<{(){})[{}{}]>}>]({((<<>()>){[<>()]{{}()}}){{[()()][<><>]}
+{(((([[(<[({({{}()}[<>[]])<(<><>)([]())>}{<[[]<>]><<()<>><()<>>>})<[[<[]{}><<>{}>]]>]<<{{[
+[{(<[[(<(<[{<({}[])<{}{}>>(<[]<>>)}]<{(<[]()>[()()])}>>{({<{{}()}[<>()]>})<[[(<>())(<>{})]{{{}[]}}][({{}[]}
+{[[<([{[(<<[<<()()>[[]]>[{()()}]](<[()]<()[]>><<{}()>{()()}>)>><[[([{}<>]{{}()})<{{}[]}<()[]>>]]})[([{{{<>()}
+((({[(<<{(((<<{}()>><{<><>}>)))[[{<({}[])[{}[]]>}(<[<><>][()()]><[[][]]<{}[]>>)]]}((({<(<>())>[({}{
+{<{{[(<<{(<{[({}<>)<{}[]>]([(){}](<>[]))}<(({}()){[][]}}[<()[]><{}()>]>>)}<<{(<[{}()]{<>{}}>[[[]()](()
+{(<<({{([<[<[<{}<>>{[][]}]<[<><>][()[]]>>{(({}{})){<()><()()>}}]>(<({{()()}({}<>)}<([]<>){[]{}}>){([[]<>
+<(<({{{([({{<<{}<>><()[]>>[{()<>}[<>{}]]}})({([{()[]}{(){}}]<(()<>)<{}<>>>)}<{{<{}<>>[[][]]}}<[{<>}[<>
+{({{(<<([({{[(()<>)[[]<>]][(<>{})({}())]}})]{(<[<(<>()){<><>}><<{}()>[[]]>][{{<>()}{[]()}}{[()<>]{<>()}}]>)
+([<({{{([[<<[[()[]][<><>]]<<<>[]><()()>>>(<{()<>}<()[]>><{<>()}<[]{}>>)>({(<()[]]<()()>)<[<>()][{}]>
+{[{<((<[<<({<{[]{}}[()()>>({[][]}[[]()])})(([{()}{{}()}]<<{}()>{{}{}}>)<([<>()])(<{}<>><{}[]>)>)>{[{
+{{([([{(<[[{[{()<>}({}())][[[]<>]<{}{}>]}]<<[({}[])(()<>)]({(){}}[()()])>{{(())<(){}>}}>]{[<{[[]()]{<>[]}}
+<(<({<{<<<([<([]<>)([]<>)>]<{{{}{}}<<>()>}>)<<{[[]()](<>{})}(([]())<[]()>)><[{<>{}}[(){}]]>>>>>(<{<[[[{
+(([({<{(<{[<({<><>}){{[][]}}>{<([]()){{}{}}>[([][])<{}{}>]}]}[((<{()<>}>)[{{()<>}{[][]}}])]
+(<<<(({{{([[<{(){}}>{(()())(()[])}]{({{}[]}<[][]>]<{{}<>}{()}>}])<(({[[][]]{{}{}}}(([][])<(){}>)
+{<{{[[({<<{{({{}()}({}{})><[()<>][<>{}]>}([<()[]>({}())][{()<>}[()]])}{<[{(){}}<[]{}>][[[]<>][[][]]]>([[<>]
+{{{[(<([[[[{[[(){}}<{}>]<{<>[]}{{}{}}>}]<[[(<>())((){})]((<>()))]{(<[]{}>([][])){<[]<>>(()[])}}>]
+(<{[([[<(<[<{[<>{}]}(<[]<>>{{}<>})>[{(())}]]>){<{(<(<>())<{}()>>]}({<<[]<>>[[]<>]>((()<>)[<><>])}
+[<{[[(({([((({[]{}}[()()])))]>[((<<[<><>][[]()]>{[()<>][()()]}>({{<>[]}({}<>)})))]})){((<[<[<[<>()]>
+<({[{{{<{[<[({[]{}}<[]>)(({}[])({}<>))]><{((()()))[[()<>]{<>[]}]}(<((){})<{}{}>><({}[])>)]][([<{
+<(<<<<<[(<<[{{[][]}{{}{}}}{{[][]}<()>}](<([]{})[()[]]>[[{}{}]{<>()}])>([{[[]()]<<>[]>}[<<>{}>{<>
+<(<[[<[[[<<(<(()[])<{}()>><(<>{})>)[([{}{}]([]{}))]><<<[<>[]]{<>[]}>{(()<>)({}[])}>>><[[[{<
+([[{[({<({(([<(){}><[]<>>]<{()<>}({})>))([([{}<>][{}[]]){[<>[]]({}<>)}][[({}[]){[]()}]])})>[({{(<(()[]){<>
+<[<{<[{(<<[[{{(){}}({}<>)}<(()[])>]<<<()()>(()<>)>({{}})>]({[(<>{})<{}()>]{<{}<>><<><>>}}<<{()<>}
+{[{({[[(({{{{<()()>{[]{}}}{[<>[]]<()<>>}}(<<<>()><{}<>>>({()<>}[()<>])}}{<{[()[]]{(){}}}>[<<[]{}>>[((){})<(
+{{(<[<(<(<{{(<[]()><()<>>)}{((<><>))[<<>{}>{()[]}]}}>{{<({{}{}}[()<>])[<(){}>(<>[])]><<(<>{}}[{}
+[{{{[[[[{(<{<[<>[]](()[])]{{<>{}}}}{[(()()){[][]}]{([][])}}><<{<<>()>([])}[[[]{}]<{}{}>]>(([{}<>]<[]()>)
+{[[(<([[[[((({<>{}}(<>())){<{}[]>})[([<>[]](<>[])}[({}[])([]())]])([<{{}()}(<>())><[[][]][<>()]>][([()()]<<>[
+<[{[{({(<(((<<<>{}><[]()>][{{}()}{[][]}])[(((){})([][]))[[()<>][[]{}]]])[[(((){})[()])[[(){}]<{}
+[{[[<[<{{(({([(){}]<()()>](([]<>)[()[]])}<<{[][]}([][])>>)<[[([]())<{}[]>]]>){[[[{{}()}[<>[]]]{<[]{}>
+[[<([([[<<<{{[{}[]][<><>]}}{{{{}{}}}}>>>[([[(<<>[]>({}<>))<([]())<<><>>>]{{<<>[]>{<>()}}}][<{{[
+({[<<<((<<<<<<[]{}>[()()]>{[()[]]{()<>}}>[((<>()){()()}){<[][]]<{}{}>}]>{{[[{}{}]<{}[]>]([[]<>])}((
+({<<[[{{<{[[{<()><<>>}<<()[]>([][])>]]([[({}<>)[()[]]](([]{})<<>[]])]<[([]<>){[]}]>)}(((<<{}[
+<(<(<(([([[[{{[]()}{<>()}}{<{}[]>[{}()]}]{{[{}{}]<()[]>}({<>()}<(){}>)}][[{<{}()><[][]>}](<[
+[[<{<[<[<({<<{[]}<()<>>>({<><>}{[]<>})><([<>()]([][]))>}[({[{}{}]<{}[]>})({[<><>]})])>]([[{<({
+<([{[[<<[({<<[{}()]({}[])>{<[][]>{()()}}>{<(<>[])([]{})>([{}[]}[<>])}}{{[<<>[]>{[]<>}][([][]){{}{}}]
+[([({((<[{{{[<{}><<>()>]<<()[]>>}<[{{}{}}([][])]{{()<>}<(){}>}>}<{<[[][]]>({{}<>}{()[]})}>
+[[[{([({{{<{[[[][]]{()()}]}{{<<>[]>[{}[]]}[[[]()]<<>>]}>({{(<>[])[{}[]]}({<>()}[{}[]])}{{(()<
+{<{{{<[{[<{(<{[]{}}{[][]}>{{[]<>}}}}[{((()[])<()()>)[<<>[]><{}()>]}<[{<>{}}[()<>]]<[<>[]][<>{}]>>]>[<[
+<[<{[[<{<[([{({}[])(()<>)}[[<>()]{()[]}]])][[<{[<>[]][<>[]]}<{<>{}}{<>{}}>>{<<()()><()<>>>{([]()
+<[{{({<[<([[[([]{})({}())]]<[{{}}[()<>]]<{<>{}}{()}>>])<[<[<<>()>]{<{}{}>[[]<>]}><({[]()}<<><>>)[(()<>)(<>())
+{<[[[<(<[<{<({<>{}}[<><>])([{}<>]<[][]>)><<[(){}](<>[])>[({}[])<<>[]}]>}{{{(<>())(<>{})}}<((<>())
+<{(<<[{[{<{<<((){})[[]{}]><([]<>)<{}[]>>>{[[[][]]<()()>]}}{({{<>()}<<>()>}{<{}<>><()[]>})}>}<[<([<()()>{()()
+{{([<{[[((<<{<<>()><<>[]>}<(()<>)>>><<[<[][]><{}<>>]>{<([]()){[]<>}>}>))]<{(((<[[]<>]([]<>)>[{{}()}<<
+([{{({{<[[(((<[][]>{<>{}}){<()[]>{[]()}})(<({}<>)([]<>)>(([])[()<>])))(([([][]){()<>}]{{[]<>}{[](
+[{{<{({[<{<{((<>())({}[]))<{<>()}({}[])>}(<[{}()]<{}<>>>({[][]}{()<>}))}{([({}[]){{}[]}]<([][])>)}}{<{({{}(
+[{(([[[([<<(<([]()){<>}>(({}<>)(()())))[((<>{})){[()<>]<<>{}>}]>>][<{{[<()<>>{{}[]}]<<{}[]><{}[]>]}[
+{<<<(<[<[{<[<({}[])>(([])<[]<>>)]<<<{}{}>({}())>{[<>{}}<[][]>}>>[{[<<>()><()()>]{[<>[]]<[]>}}[<<<>[]>{[]()
+([(((<<(<[[<[<{}<>>(<><>)]>([<{}[]>{<>{}}]({<>{}}[()()]))]](<({<<>[]>({}[])}<[[]<>]{<>[]}>)(<{
+([{({{{[(((<<{[]()}<{}<>>>((<><>){[]()>)>({<{}()><(){}>}<[<>()]>))){((([[][]]{<>{}})[([]<>){<>[]}]
+<(({{{[(([<[{<(){}>([]<>)}(<[]><()<>>)]><<([()[]]([]()))>{[(()<>}<{}>]}>]){{[{(({}{})<(){}>){[[]]{[]
+[<{(<({<{((<<<[]<>>([]())>(((){})[[]()])>{[[<>]<{}<>>]}){[<[<>[]]({}())]{{()[]}<()>}]})<([[([]())<<
+[[<<[<{{[{({<[()<>]{<>[]}>{([][]){<><>}}}<[[{}()]][<<><>>{{}[]}]>)}{<{{({}<>)(()())}[{{}{}}[{}()]]
+({<({[{[{(([<<()()>{<>[]}>[([]<>)<()<>>]]{<{<>()}[{}{}]>((<>{}){<>{}})})([<([][])[[]{}]>(<[]()>{<>
+{[[((<{[[<<({<[]<>>[()<>]}{[()]{<>}})>[<{<<>()><()[]>}{{()[]}<()<>>}>(([{}[]]))]>[[{({<><>})}
+{{(<[{{[{<[({(()){{}<>}}(<{}[]>[[]()]))]>}({(<((()[])((){}))<{<><>}[<>()]>>)}(<<[(())<{}<>>]{[[]]<{}
+<{{([<<<<[([<[<><>][[]]><<(){}>[()()]>]<{(<><>)<<><>>}([{}{}])>)][[([<()()><<>()>])(({[]<>}([]{}]){<[]><[]
+{(<<[[<{{((([<[]<>>[{}<>]][([][]){{}{}}>)(<<<><>><[]{}>>{{(){}}[<>{}]}))({<(())[<>()]><{<>{}}(<>[])>}(({
+[[[([({([<<[[[<>{}]{<>{}}]<[<><>]{{}<>}>]>[({[()()]<<>()>}{[()()][{}()]}){({{}()}[(){}))}]>[(<{[()<>
+[{{(<<<[{(((<<()<>>([])>({<>{}}<()[]>)))[{(([]){()<>})(({}[])<{}})}<{([]{})({}())}<(<>[])<<>[]>>>
+{<<<<[{[{({{[<<>()><{}[]>]<[[]{}][{}{}]>}(<({}{})<()<>>>{{()<>}})}{[[{{}{}}[{}{}]]<[<><>](<>{})>]})(([{[<>()
+<(<[<{(<{[{<{[[]{}]{{}[]}}>[{[[]<>][{}{}]}(([]())(<>))]}<{{[{}{}]([]{})}[({}())]}{<<<>()>>([(
+<{{[{[<{[[<[{<[]{}><<>{}>}]{({()<>}(<><>)){[<>[]]}}>{([[<>{}]({}{})](({}{})<[]{}>))<{[{}<>
+{{<<{<<<[{[[([[]()][()()])(({}()))][[({}[])<()()>]]]{<[<{}[]>{{}{}}]>}}[[[[([]())]([<>[]][[]{}]>]]
+[[<<[({{{(<[(<()<>>[<>])]([(()<>){<>())]([<>[]][[]<>]))>{{[[[]()]([]())]{<[]{}>{()<>}}}[<([]<>)<()>>({<>{}}[<
+([[([<{<[<((<(<>[])(<>[])>(<<><>><{}[]>)){<<{}<>>>({{}{}}<()[]>)}>[{{(<><>)(()<>)}[<<>[]>]}]>]<{{
+{{{((<<{[[{<([[]{}][{}<>])>}<[((()())<()<>>)[[[]{}]{[][]}]]<<<[]{}>{{}[]}>(<<>()><(){}>)>>](<
+{(([[{{<[[<{(({}<>)[<>[]])}<{({}{}){{}}}[[()[]](()())]>>]([<[{()[]})({<>}[<>{}])>{[{{}{}}{(){}}]{<{}{}>}}])
+{([(<{<<({[<[{()()}<[]<>>]{<[]{}>}><[[<>][()<>]]>]{<{{[]{}}<(){}>}[({})]>{{<{}{}><()<>>}([{}
+{{[[({{({[(([{{}()}[{}]]({{}<>}([][]))){({{}<>}[[]{}])<<()<>>>})]{(<[<{}{}>{<>()}](({}())((){
+{<({{<<{{([{{{[]<>}{<>{}}}((<><>)<()<>>)}[<[{}<>][()[]]><[<>()][<><>]>]]{{[[()<>]<<>[]>]<(<><>)
+<(<[(<<[[<<<[({}())<[][]>](({}<>)[{}<>])>>[<{{{}}<()<>>}<(()<>){{}{}}>>]>({{<[<><>](<><>)>[(<>{}
+[((<{[{{(<{[({{}[]}((){}))([[][]]{<>[]})]<{<{}[]>[{}<>]}[<{}()><{}<>>]>]>)}}]}{{{(<[(<{{()()}}>{[<{}<>><<>[]>
+{([<<{(<([[({{{}<>}<(){}>}<<()[]>{<>{}}>)((<[][]>[<><>])<<[][]>{<>()}>)]((<{<>[]}{[][]}>[[<>()]{<>[]}]]{{[
+[<{(<{([{{(([<<>()>]{<(){}><()<>>}){(([]{}>)<(<><>)>})}({({[<>]{<>[]}}[[{}<>]])}[{<[()[]]<{}<>
+{[(<(<{(<<[{[<[]()>(<>[])][{{}}[()[]]]}{{[[]{}]{()()}}<<<>>[[]()]>}]>{{<[<{}()>([]())]({(){}}(()<>))>([(<>(
+{{([[([[[<(({<{}<>>[<>[]]}{([]<>)<<>{}>})<{{[]<>}{{}<>}}([()()]<<>[]>>>){{[[()<>]]<((){})<[]{}>>}{<<[]<>><()
+<({([[[[[({[[{{}<>}({}<>)]({<>[]}[<>{}])][([<>[]](<>()))<([]())[{}{}]>]}(((({}[])[()[]])[{{}{}}(<>)])(<<<>
+[({{<{[([(((<{[]{}}{<>()}><[{}<>>{<>[]}>)){([<{}{}><()[]>]<([]{})[{}{}]>){{[[]]<[]{}>}((()[])[(
+(({<[<<{{[[<{(<>{})([]())}([[]{}]{{}()})><[<{}()><{}{}>]<<<>()>[[]()]>>]<[<<()[]><<>()>>[{{}<>}[<>]]]>]
+((<[[<{{{[({<(()[])<()<>>>})]{<(([()()][[]]))({[[]()]{[]<>}}{[<>()]})><<(({}[])[{}{}])>>}}}[[[{{{{[]{}}({}[
+([<[<{{{{[<<{{<>[]}([]<>)}><{{()[]}[<><>]}{<[]>[()<>]}>><{[{[][]}<()[]>]({[][]}(()<>))}<{(<>())(
+{((<(([[<[(<[{()[]}([]())>>[<[<>()]<[]{}>>(<()<>><[]>)])<(<{()}>(([]<>){<>{}}))<[[[]<>]{[]()}
+[(<[([([{{{<([[]<>]<<>>)[{<>[]}{{}<>}]}({(())[{}()]}[<{}<>>{<>()}])}([<[(){}]([][])><(()())
diff --git a/2021/src/test/kotlin/Day10Test.kt b/2021/src/test/kotlin/Day10Test.kt
new file mode 100644
index 0000000..7e9092b
--- /dev/null
+++ b/2021/src/test/kotlin/Day10Test.kt
@@ -0,0 +1,22 @@
+package be.vandewalleh.aoc.days
+
+class Day10Test : BaseDayTest(10) {
+    override val example = """
+        [({(<(())[]>[[{[]{<()<>>
+        [(()[<>])]({[<{<<[]>>(
+        {([(<{}[<>[]}>{[]{[(<()>
+        (((({<>}<{<{<>}{[]{[]{}
+        [[<[([]))<([[{}[[()]]]
+        [{[{({}]{}}([{[{{{}}([]
+        {<[[]]>}<{[{[{[]{()[[[]
+        [<(<(<(<{}))><([]([]()
+        <{([([[(<>()){}]>(<<{{
+        <{([{{}}[<[[[<>{}]]]>[]]
+    """.trimIndent()
+
+    override val part1Example = 26397
+    override val part1Answer = 294195
+
+    override val part2Example = 288957L
+    override val part2Answer = 3490802734L
+}