s = input()
n = len(s)
l = 1
for i in range(n - 1):
    if l >= n - i:
        continue
    for j in range(i + l, n+1):
        t = s[i:j]
        if t[0] == t[-1] and t == t[::-1]:
            l = j - i
        # print(i,t)
print(l)