s = input()

x = 0
for i in range(len(s)):
    for j in range(i+1, len(s)+1):
        l1 = s[i:j]
        l2 = l1[::-1]
        if l1 == l2 and len(l1) != len(s):
            x = max(x, len(l1))

print(x)