S = input()

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

    l = i
    r = i+1
    cnt = 0
    while 0 <= l and r < N:
        if S[l] == S[r]:
            cnt += 2
        l -= 1
        r += 1
    ans = max(ans, cnt)

print(ans)