diff --git a/06/f.py b/06/f.py
new file mode 100644
index 0000000..23f190f
--- /dev/null
+++ b/06/f.py
@@ -0,0 +1,19 @@
+import os
+
+input = open(os.path.dirname(__file__) +
+             "/input.txt", "r").read()
+
+index = 0
+index2 = 0
+buf = []
+for x in input:
+    index += 1
+    index2 += 1
+    buf.append(x)
+    if len(buf) == 4:
+        if len(set(buf)) == 4:
+            break
+        else:
+            buf.pop(0)
+
+print(index)