S = raw_input()
pail = [[False for j in range(51)] for i in range(51)]
N = len(S)
ans = 0
def solve(pos, res):
    global ans
    if (pos == N):
        ans = max(ans, res)
        return 
    for i in range(pos, N):
        if (pail[pos][i]):
            next = max(res, (i - pos) + 1)
            solve(i + 1, next)
            
for i in range(N):
    left = i
    right = i
    while (left >= 0 and right < N):
        if (S[left] == S[right]):
            pail[left][right] = True
        else:
            break
        left -= 1
        right += 1
        
    left = i
    right = i + 1
    while (left >= 0 and right < N):
        if (S[left] == S[right]):
            pail[left][right] = True
        else:
            break
        left -= 1
        right += 1
for i in range(N):
    for j in range(i, N):
        if (pail[i][j] and not(i == 0 and j == N - 1)):
            ans = max(ans, j - i + 1)
print ans