def longest_palindrome_after_deletion(s):
    def manacher(s):
        s = '#' + '#'.join(s) + '#'
        n = len(s)
        P = [0] * n
        C, R = 0, 0
        for i in range(n):
            mirror = 2*C - i
            if i < R:
                P[i] = min(R - i, P[mirror])
            a, b = i + (1 + P[i]), i - (1 + P[i])
            while a < n and b >= 0 and s[a] == s[b]:
                P[i] += 1
                a += 1
                b -= 1
            if i + P[i] > R:
                C = i
                R = i + P[i]
        max_len = max(P)
        return max_len

    max_len = 0
    n = len(s)
    if n == 1:
        return 0
    for i in range(n):
        new_s = s[:i] + s[i+1:]
        current_len = manacher(new_s)
        if current_len > max_len:
            max_len = current_len
    return max_len

s = input().strip()
print(longest_palindrome_after_deletion(s))