s = input()
N = len(s)
ans = 1
# (i, j]
for j in range(1, N + 1):
    for i in range(j):
        if (i, j) == (0, N):
            continue
        if s[i:j] == s[i:j][::-1]:
            ans = max(ans, j - i)
print(ans)