S = input()
N = len(S)
ans = 0
for i in range(N):
    center1 = i
    cnt = -1
    for j in range(center1+1):
        if 2*center1-j >= N:
            continue
        if S[j] == S[2*center1-j]:
            cnt += 2
    ans = max(ans,cnt)
    center2 = i
    cnt = 0
    for j in range(center1+1):
        if 2*center1-j+1 >= N:
            continue
        if S[j] == S[2*center1-j+1]:
            cnt += 2
    ans = max(ans,cnt)
print(ans)