s = input()

maxlen = 0
for i in range(len(s)-1):
    for j in range(i+1,len(s)+1):

        if s[i:j] == s[i:j][::-1] and len(s[i:j]) != len(s):
            maxlen = max(maxlen,len(s[i:j+1]))

print(maxlen)