S = input()
N = len(S)
ans = 0
for i in range(N):
    ret = 1
    d = 1
    while i - d >= 0 and i + d < N:
        if S[i - d] == S[i + d]:
            ret += 2
        d += 1
    ans = max(ans,ret)
    ret = 0
    d = 1
    while i - d >= 0 and i + d - 1 < N:
        if S[i - d] == S[i + d - 1]:
            ret += 2
        d += 1
    ans = max(ans,ret)
print(ans)