Envío 3472

Código

def string_edge(s):
    left = 0
    right = 1

    while True:
        right = s.find(s[left], right)

        if right == -1:
            break

        while True:
            left += 1
            right += 1

            if right == len(s):
                return left

            if s[left] != s[right]:
                left = 0
                break

    return left


s = input()
print(string_edge(s))