S = input()
n = len(S)
ans = 0
for i in range(n):
    cnt = 1
    l = i - 1
    r = i + 1
    while l >= 0 and r < n:
        if S[l] == S[r]:
            cnt += 2
        l -= 1
        r += 1
    ans = max(ans, cnt)
    
    cnt = 0
    l = i
    r = i + 1
    while l >= 0 and r < n:
        if S[l] == S[r]:
            cnt += 2
        l -= 1
        r += 1
    ans = max(ans, cnt)
    
print(ans)