diff --git a/input/6.txt b/input/6.txt
new file mode 100644
index 0000000..12ab400
--- /dev/null
+++ b/input/6.txt
@@ -0,0 +1 @@
+jghhttcmttdwwfjjjpqjqllwvwffswwqmwmddvndvdrrcwrccfncfcgcjjpjrjzjggczgglhllbzlztlzzswwbqqrvrvqrqcrclrccrbrpbbzhbbzvbbwrwswqwqqgmmgqmqmdqdhdmmfnndpdvvdvdbbmgmqgqgqmqrrsbsrrzcrzrcrvrddpqdpdwwsvshvshvshszhshddjllbjljjwhjwhwppbssdccvzzmvvwrrrhmmbdbggqhgqglglgrrdbdjddjvddzpznzmnnpgnppnznzvzbzvvdtdwdttnzzdpzzqjzjzllhglghgttcbtcbtbjbssqcqtcqtqvttvpvqvggbsszjsjqjllfgfqqhllvsvmmjhhbdbzzrwzzggdfgdgcddgmmjnjhhhgvgwghgfffclffdmmmlclzclzzqgqjqzqwzqzbbbljlplnlrlqlqlhlvlmvvlwltwtqwwznndpdttjjrllpptnngjnnzppjhpjhpjpjmjpmjpptzppjpsprpbpmmshmsmqqnhnjhnjnccdnnqhhgfgmgnmnvvtwvttcbtbnbcnnhjjnpphjpjppshsppmrmrbrlrzlzjlzzvssvfffsjfsjshshppchppprpcclhlmmgwwsddgbdggcqqhsqqbdbzzdffmpmvmpptppjrprrgvvgrrztrtllnblbffpgprpqqwcwjwcjcbbjgbbsgsbgbgwbwrrbcrcjcnnvlnlmnnwcncbcrrgcrggtqqgbbqsqhsqslswsdswscwssbqbppczzpmmnjnfjfpjpqpddpbbgrrnqrnqqnwqnntsnsdnddvhhgrgmmgzmgmwgmwwmfwwnqnjjgqghqhhpzpmpbmpbbqvvjjlvvddcnnglnnhpnhhjghgrgjrjqqgtqggmzzbdbssbpssrjsrsbbpzzsgzzpcpwwfgwfgfccslsmlltlnttpvvcbvbqqqqvlvplvvmnntstffvhvvwfftltjjtftbftfqqnbbmnmqqwbbldbldbddtldtldldbllsggdqgdgfgtggglmmgfgcfgccgttgdgdvgglhhvbbnzbzvbzzvtvntvntvvwgvgcgrrmbmnmttzlzgllpmlpmmscsncnnnfrrvqvmvsvsrvvbvpbbvsvssdnnmvnnnggpmpbbqsqwssjwwtnwwhbwwmcwwjfwfhfvvsnsqqwmmrfmrmcrchhpqprpzpmpzzqqmqbqjjbffjnnhphdpdjjbcjcsjcjcdcrddscsgsqgsqggcscrssscvcncfccptcccjgjqqlppjbpjpgpzpgpqqzwqwcwnwccmnnnwrnrttjqtjtllbslsrlrggjrrjwrwmrrcbbnddzcdzcchqqrhhcrcrlrmrcchcpcmcrrlqltlhttdhhjrrzllwjjfvvzccmwwtlwwhpwwssfdsfdsfsddwbbfsfqfwqffhqfqvqwwhfhrrwhrwhrwrzrwrzwwbsblslzzrwzwdwnwznnbsnsbbgffjppvqppbmmdffgghrrchrhfhthqthqhvvrcvrrfvfbvffmmbjmjbbwhhvqvbvjjfzjzvvwnvncvvdssfffjfhjhbbdhdlllmrlmrllbtltbbhnnczzwjzwjwllvtvmvpvvmmfnmnwmwjwrrqtqlltwllwrllsvvdrvrnvrnnsjnjfnnmpnpgnglnggbnbmmcmddhrdrjdjtthssdbssjtjvttqwqppwbpblljnlnljlfjffvddtzzqfzqqjttqhhhvppghpghpghghjggsrrczzqvvbjbbbglldcdrdqdpqpwpffnjnhnthhtlhhrdrcrwrvrlvrlvrvprpccmffqzffdbdhhwjjgmgzzqhqnqsstltjjzszpsppdpnddrnrmrllhtwnlhgzgvsfjfmgfcnnzqhbfztnzhnctmjjhvzrhjcptzqqtstlmrgnbcpnctjgswhfcmtzgsndfzdlqsrlcjrssmjndgrzgvtgfjwtcqwnzmrgtgngcwcwzvttqcdwqspzldfmzgmfclwgqvvvqhhhswpdjlbpjpppdljbdjrbblbrtftdsmvmfpftdlvhdphzbcwwwjvmsjczbtblwbtszmbcmpbdqnwcgcltbdzbsvtjhlqgrsgqzztqrvmswtzgvsjslgvjcvhqftdcmwqwhgwrmrpfdqvfqhczlztrhjqlppchgspfjwzvfsncdhgnlnnshwsbvqmqwtldtmshhqpqbdzqlwfvvbbzwqvlvqdwcpbtrsrhmrjnzmqjttthhbbdjwtzhwjcvhzrtgfwltqhmzwtqbgjjpphlfwfhgctmwpqrmngfrfmbmcqpqcrsmzhjzdzbppbfwpgdtdjvjdvbwfcbddjpjbgtrjtddlpvnppcwhbbgpqgmcrwmfsvqspdvctvljbhcgnllzdpjmjdqwflrfqrsfqnhcsbtszjfmqvjwmcsghwcssbnzzpsggbmpdqrlctrcrmbzlnnqcfmrpfwsnjcggtqncwddsjjzwvlnfpwjlrgwrrvfhgtjwqlblnsnrddjqqtwtzrvfqfqcjhbwtlmfsfgpzgtdddtlvqlqgjwpprpzvdhvlfjbqqflbnvgsgblfpcqprlqrhrrddjjftbmfgghrrrhmttmnfzgmrzwcscnsmdnnddsbdjswhwmjfjnfvjbtcqjlflzjsqqhldcdsbjttmvmcdbwrfwdlllbbjhbmdhnfgwmmbpbsrmqptppqzwtncnwwsjjrchgpvdcsspfqpczmsqfrgvfgsnhfmplrnhzddlbvnthltpwbbzdwwnmhmllwfphhfpnghgdzlzgpbvsphbhvfmcvqpqvdsjjbnbsdvccbmgwdbgsnhpgfshzzznjdbngsrqpwhqjqdfsnmngzznwgvqrtjmzcmbbqjgjcdjdqbmdrgvqflsstqhgsgpfnmzvrdgztlzlhvdjdcslwbgldwjwftvczvtbpdtdqtqshqrbpvpgbfbtnnlmzrhdtsjdlllbtwqgcfphssqmszmbllnbpwvhfdllwtcbqccmbtscmsvppjjrcpswgtzgvhblvbmcddhhgqghbtwzffscsvzgwjdfldccbcfptpmmfbwqzlqhdrcdvhpnwvddqcrwwlmtgvrcvlbvtblhhmhdrvvnpmrdqsgjdrfprfcmtfsbrmsglfjcnjwvpjqlptrbmrqcrdfccmfvhqzrmwqbbmtmjrbnmvzdbwcfpwjzrjrhzrncpwptswhnrgsdpdfjqcjhnvvftgzdccpsgdqcqzfvbtftrzljqmjbgmmlrdlvpwqddmdhzsslzlnvfrblfzfpwtvhpwhmqmbzvchndbzfswtmvcprhlssmncfdqcpzjczptptgdzpjvrqtrlcgbhlqqwvnsrrvtllldbhztgnlmjbmqmgcpcbwtthnhwghnqgvqtnnltbzslmmbjbhqtrmqbgccphjsgwbtstvjnpjjqsdwdsgcrjgznntsgvlrgzmbnzdmbghrmtscppgmztfbsqczzvhsmjmmclhrcbgnvjbgffgbrhrdwccplpdfzcljgfntjlzmsqrwrmdqbclffbfpscddcfsbpsnnphjvjwsfvbprsgpcnbrblvvqfvngbhgmmglzzfmmpnnrphwrvqnmffwpsmmrlhmnsdvbdgjlrjmsdzjltgmjfplrrfmgbhzltzzfpwtqcqwbgsgwfbmntzsvtqqtnrhbtbnshfmwwzbvtsqmtsfssrcvgngvvhjlcnfsvltpsdjspgmmrqttcsltjzqglpspmgrnbrtnbtnjzprqmtfhgczjrlqdhsjqjbhpnwhrffmhvqfmlzcpfflptgqwthfzvspbjjdwmmbnttbztzpnjmlstgmgqbptdncqgbdbdnqwslwhfrdfvmbbqlzhdptpfrhnvcchpddngslzzrhsrwclpccbqhcscbzcpdtwmppvrpjnnjfgrswndtzprjnsvvdwwhhbcsglnwwptptdzgsmbwppdrhwpqhzlgfcsqtfzvqdvcsbtbqvtfvwlcdrwttgmwhbjlqphclqfzmlb
diff --git a/src/s6a.d b/src/s6a.d
new file mode 100644
index 0000000..bb2097c
--- /dev/null
+++ b/src/s6a.d
@@ -0,0 +1,12 @@
+module s6a;
+import util;
+
+void main() {
+    string code = readText("input/6.txt").strip();
+    for (int i = 0; i < code.length; i++) {
+        if (i >= 3 && Set!char(code[i - 3 .. i + 1].to!(char[])).items.length == 4) {
+            writeln(i + 1);
+            break;
+        }
+    }
+}
diff --git a/src/s6b.d b/src/s6b.d
new file mode 100644
index 0000000..b9a0944
--- /dev/null
+++ b/src/s6b.d
@@ -0,0 +1,12 @@
+module s6b;
+import util;
+
+void main() {
+    string code = readText("input/6.txt").strip();
+    for (int i = 0; i < code.length; i++) {
+        if (i >= 13 && Set!char(code[i - 13 .. i + 1].to!(char[])).items.length == 14) {
+            writeln(i + 1);
+            break;
+        }
+    }
+}