L = [str(x) for x in str(input())]
n = len(L)
c = 1

for m in range (1, n):
    for l in range(1, n - m + 1):
        M = L[l : l + m]
        N = M[::-1]
        if M == N and c < m:
            c = m

if c == 2:
    c = 1
print(c)