23A (Accepted)

src/A. You're Given a String....py

@@ -0,0 +1,17 @@
+# https://codeforces.com/problemset/problem/23/A
+
+def solve():
+    string = input()
+    best = 0
+    for offset in range(1, len(string)):
+        for start in range(len(string)):
+            i = 0
+            while i + offset + start < len(string) and string[i + start] == string[i + offset + start]:
+                i += 1
+
+            if i > best:
+                best = i
+
+    print(best)
+
+solve()