s = str(input())

def check(s):
    n = len(s)
    for i in range(n//2):
        if s[i] != s[n-1-i]:
            return False
    return True

ans = 0
n = len(s)
for i in range(n-1):
    for j in range(i+1, n+1):
        if i == 0 and j == n:
            continue
        t = s[i:j]
        if check(t):
            ans = max(ans, j-i)
print(ans)