def manachers(s):
    n = len(s)
    if n == 0:
        return 0
    s = '#' + '#'.join(s) + '#'
    n = len(s)
    p = [0] * n
    C, R = 0, 0
    max_len = 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(max_len, p[i])
    return max_len

def main():
    import sys
    input = sys.stdin.read
    s = input().strip()
    max_len = 0
    n = len(s)
    for i in range(n):
        new_s = s[:i] + s[i+1:]
        current = manachers(new_s)
        if current > max_len:
            max_len = current
    print(max_len)

if __name__ == "__main__":
    main()