S = input()
N = len(S)
ans = 1
for center, c in enumerate(S):
    tmp = 1
    for idx in range(1, N):
        if not (0 <= center - idx and center + idx < N):
            break
        if S[center - idx] == S[center + idx]:
            tmp += 2
    ans = max(ans, tmp)
print(ans)