#!/usr/bin/python
s = raw_input()
n = len(s)
res = 0
for i in xrange(n):
    for j in xrange(i, n):
        if i==0 and j==n-1:
            continue
        t = s[i:j+1]
        if t == t[::-1]:
            res = max(res, j-i+1)
print res