S = input()
N = len(S)

def check(i, j):
    # i ~ j
    a = S[i:j+1]
    b = a[::-1]
    return a == b

ans = 1
for i in range(N):
    for j in range(i, N):
        if i == 0 and j == N - 1:
            continue

        if check(i, j):
            sub = j - i + 1
            if sub > ans:
                ans = sub

print(ans)