diff --git a/day6/input.txt b/day6/input.txt
new file mode 100644
index 0000000..6359773
--- /dev/null
+++ b/day6/input.txt
@@ -0,0 +1 @@
+dfsfmfbbbjnbbpddfcfjcjbjwjqqbtbntnhtnncfnfpnffwpphwppvbvtvztzszfzhhnqnvnpppmzmczcmzczbznnbssbhhvghhzqzvzttjvtvcccdhccmvccgdgttghthppwlwqlwwcswspsfsdfddhwwzlwzwttlglttsjjthhgcgfcfhfhtftrffwcfcsfccnntmmpvpgpfgfsgfflgfgmffbmmqsmqmmcqqmjjzczwczzpjzzgtgnnqqvdqvqllbttftgtztcztttlslrslrlfldljlwjjnvjjmrrhdrhhflhffgnfnjffmvmvjjspsvvrcchhgngwwdwbwwfhwffmggbsgspsjsfjjdwwbtbdtbdbgdbbbzhzvhhwpwlwfwfswwrgggmggssfwwdrwrccssjttltrrnggdbggvzzzrfzfwzfffnfnmnnzmnznpzzdtzdttbvvgffmnfmfmbbqppcgpgtgpgggcwwlpplslbslblhlmlfmlmldmmjhjjgllglhlssswcssprrqrjrhrvrffpfnpfnppzgztgtdgtdggftgftggqrgrnnqpnpgnpnggsjsvscsnswshwswfwfwqffcrrmprrrcgrrggmnnmzmwzmwzzgzzhnzzthtggtmmdrmrbmmqwwjswwphhzvvjqjrrvzrrmssdvdlvvlhvvjggbwbrwwjqjqmmfllttvpttdvtdtddrttpltpllzrlrwlrrvcvpcphcccqwwtpwwbmmtntfntftvfvfqvvwnvwwvhhlccvrcrlclcqcvqqsvvfjjqmmfhfvvctczzlhlsslpspfsswnsnzsspzpccmssmpmbpbmmvnvsnvsszttrppvgpgnncllrvlrvllcvlvwvhvghgvvnhvvmffclfccvwcvccrwrhhrffqrqcrqqhbqhqssmzsmzsmmzrztzllmclmmbgmbbrmrgrwrgwrrgngvvtqqpbqpppgbgccsjjcmmtdmdjmmjcchvchhbccnjngjjnwjnnrvnrrsqshshszzqnngbnnrnggvwwlzwwlqwqmqdqrdqqrhqhffpgffqgqdggfjgglfglgvgjvjmjtthghrhvhgvhvnncnwcnwntwntnjjqjwwrdwddsggfddnhnsnvsstbbjddfhddhbddwbwbnbrnnrhrqhqdhdllvbbnzzbmbttpjjngnqqcffrsrnsnnhzzgllgvlvcchfhzzmzrmrggdvgvgqqwnqqpdqqvjjvnvhnhhgvhhgllhlzlclbcccwppztzhhvmvzzzsbzbppvdvdtdtdvdsdlsscnnqhnhgngghrrzprzzpddmvvhcvvprplpnlppscctzthtptspttmftmftfjjdfdjfjrfrfbfcchmhnnbddwzwvvpvrvnnslnlnhlnhlltslttqpqvvgzvzsstcstsrtrbtbbzmmzrzqrzqqnmqnnpjpttwgtgzgqqgmgnnzgzrggpbggvssqvssmhmshmssvlvlmvvnhnhddwbbllffgbffbbztthbhdhdghhrccfmfrfmmbdbfdbffzfgfrfqqptpgpjjlvvbjjdzdbbszslzlldnngwgddbmbpbwwhphnhmhhlthhgfhfvvpmvmhvmvdvsddsjtzvfmpsrwrrzgcvnnllfjmvfptwncppfmgqbfzrdpnfddghsqfmnqfwfslrsgjmqtfqwhdddsbhtbtpswcbfppcbhzfzbsqljzndcsrlhrrtstgfhhfsqqrwgnncsmstdmjvfjhqnrczlftzzzhqdzjdcdqcgfpmbqntdhzcvbtpssrvmgjwzwfvtpsrsrwrvrsjgrmzqzvbttscldsnnwzvmlztnnpdjrwvhshpdwgvhmlrnhtfccjnldlnhtfncfjjjztjmhrdqpvhggtqzwjsvwdzhdmwhsmgzjcwzqzlwbrlzsmlwhpjvflnppvrbgrsblmjpnqvgpjbpwbjgjqzwvjbgcplccjgbfwlblzfjqpwszbqbcnlbmfmqpmgspscgfdgfwnmcdzcqnjznndjcvlblszcnpflbjqltpfzhffdbwbshtpnwwlspltpcrvbdtflwbjrfnvrflqpgqtjzqwmmsdvtsmgjtrtbrzchwhpfsznjqcbrjcvwqgrcsqpvfzhrdlmnvvhjzpgpnlrmqfvcnlrlcfjblfcgvngdjfdczsrtnnwjndsfcsdlhdnbtplfnhsmmbldmsjwcblghhgqwbnjvqbqhddrmrtncvwnchsfpddzgrrtzntmwnmdwlrvnjgnzjqvptztnqnqmcjmmrhmtstgdvhffbbmphnbtsdmpmscsfdbnfnchrhhjpsfhhswfszgqfcbdbgnrqhrflpfgfgdcrjvrwbvsfmzzhvzvqzgshcqzlfcljnlgshdlhwdchhhvwlshwdrgjfbnptqqglbpcfgrmqjhqvlbzdwgnzfzlpcpjzqwhbfjljszvjdsrmfzntgnjflhnwhpfrlbpvgzmbqwzlgphmbvbfdqfgqqbhzzvrjftnwjzhlrqccwcfzvntscnbfcsrqqnvlvhszpgwtrzjrqbtslctbhtbczwtmsgwczncbjmzqvnthpwjmsbsjnfpsmghnvtqjjnjfwtnmlthrlcpqhjpnvnbbnwrdjfshwhpdwmsbngfhbhsqphlqspcgzwrgfjmqqtlsfgnvqtdgnhmdvvqzjwlhsnvjczbssrnlhwdmdthmtprjjfttfzbbswfwsvvslfnbcvprzhtcqwdrzjrnjjctqfsjrsddlhzcnstqfppjlqhvcbjbfwndwdtdfvnlwgvdvhzzrqthdhdmddfdwschmpwwrnlgsldzhgjrlmtzrnrrtqfctvbncpcjlsvnwjvhgnbshhwlqhtjghvrctlvngjgjrlgshhwscrdvzjqtfrrbssvqlcjjdljpmlzfqqnqmffpsbvgcqzqdjwczbqwjgfvpdgjglnqdshppcsqcmszhrbcpnhjnczlhwsbnfnzsczjvmftngqcvhgpgwlzbmjnmmdvdjfrcwnjrncvfstrvvqsstphmqdpwjqhzgppmgwlgjhgfwqgmjrlsvqpfqznvbqzgtngvpbpttzvngjwtrjgdnvdggzlnmpgbzhtnfnrhgwvhnpqdwfdvvftzllpqblgdglclwtwbchlvwcmmvtchlntlghztfvgfjczcbqmzgnqmrjcmqvjmjhfpztjcvclblmrctzfmsdfvfpwdcbsglgrsjqcgtcblhbtgcgjlwhhqnwhdnwzlhvphtvmlfnbfmgpnnbzqtdtzqrbhfljlwstlbscnrsvhrbrcthvzcngrttddcjqhtmsfpsgldgtsgjtprsttlssmrrfjmrddqvnqcfmphbnjtdsqvptrdzqbqfjqtnrqtjgdpbrlzrlvwcbcqbcmncfmwcpdhgpjdrdcmrqnflsqbllrqslmhsljwghnwcjwvhchcnlgppmphbqtcdfzjpcqcgsjzvmgfjgfsvmvjfqvtpffbpmhnnnrjmqhhhrhrqfqdwzdvzssslzvqhngdpszztgrvjntcpzhbfmhbpvcndsjbtnwgpmztpbrtjmfqrsvndrspdqmlsbldgghfflncszhnsttfslvwhvfnsmmhbbvjqslsjfqplndndwmbmvgchgvhzclrcnhvgbgmpctrggvqpvqvgvncmdwhpmwhzwhlgsnlnwggfbbvdvqrrsmhwzrrpgrjfshzgzjpfwjhpqmqhbjlwhwsfszlshpzprvgprlprrvlcrmbttjrpqsrdcdfwdrzbcfjpvrlrjjdwhbspqmrblvtldqdhtjtjphpqswgvqfftdgqrtjgsmthlhvlcqrwlqtthwjgrcpwcnsqtssqzpzqptrwjjdfchfmmsrsccnlvqbdmbcdjmhpgvnnlttfhggfphvbwqtcztbnsflztcfpbcpjbcmsplhjdbsmzhgnmfrhscmwmfqbljvhgllvvgqzphzbswdzlhmpcvnntczrcnqvlphhjdjjjnhfzzcjjsdlfccwvswvjfgvmlnpvjvcbpglsgtpj
diff --git a/day6/marker b/day6/marker
new file mode 100755
index 0000000..213c009
Binary files /dev/null and b/day6/marker differ
diff --git a/day6/marker.c b/day6/marker.c
new file mode 100644
index 0000000..44addda
--- /dev/null
+++ b/day6/marker.c
@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define WINDOW_SIZE 14
+#define START_OF_PACKET 4
+#define START_OF_MESSAGE 14
+
+void shift(char*, char);
+int unique(char*, int n);
+
+int main() {
+    char buf[WINDOW_SIZE], c;
+    memset(buf, 0, WINDOW_SIZE);
+    int charNum = 1, result = 0, result2= 0;
+
+    while ((c = getchar()) != EOF) {
+        shift(buf, c);
+        if (charNum > START_OF_PACKET - 1 && !result && unique(buf + (WINDOW_SIZE - START_OF_PACKET), START_OF_PACKET))  {
+            result = charNum;
+        }
+        if (charNum > START_OF_MESSAGE - 1 && !result2 && unique(buf, START_OF_MESSAGE))  {
+            result2 = charNum;
+        }
+        charNum++;
+    }
+
+    printf("%i\n", result);
+    printf("%i\n", result2);
+}
+
+void shift(char* buf, char c) {
+    for (int i = 0; i < WINDOW_SIZE - 1; i++) {
+        buf[i] = buf[i+1];
+    }
+    buf[WINDOW_SIZE - 1] = c;
+}
+
+int unique(char* buf, int n) {
+    for(int i = 0; i < n; i++) {
+        for (int j = i + 1; j < n; j++) {
+            if (buf[i] == buf[j]) {
+                return 0;
+            }
+        }
+    }
+
+    return 1;
+}