import sys, math
sys.set_int_max_str_digits(0)

def f(S):
    N = len(S)
    longest = 0
    # 奇数長
    for i in range(N):
        cnt = 1
        for j in range(1, N):
            if not (0<= i-j and i+j < N):
                break
            if S[i-j] == S[i+j]:
                cnt += 2
        longest = max(longest, cnt)

    # 偶数長
    for i in range(N - 1):
        # i, i+1
        cnt = 0
        for j in range(N):
            if not (0<= i-j and i+1+j < N):
                break
            if S[i-j] == S[i+1+j]:
                cnt += 2
        longest = max(longest, cnt)

    return longest

S = input()
print(f(S))