import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

S = read().rstrip()

N = len(S)
answer = 0
for i in range(N):
    for j in range(i+1,N+1):
        T = S[i:j]
        if T != T[::-1]:
            continue
        if len(T) == N:
            continue
        if answer < len(T):
            answer = len(T)

print(answer)