S = input().strip()
ans = 1
for i in range(1,len(S)-1):
    cnt = 1
    for k in range(1,len(S)):
        if i-k<0 or i+k>=len(S):break
        if S[i-k]==S[i+k]:
            cnt += 2
    ans = max(ans,cnt)
for i in range(len(S)-1):
    cnt = 0
    for k in range(len(S)):
        if i-k<0 or i+k+1>=len(S):break
        if S[i-k]==S[i+k+1]:
            cnt += 2
    ans = max(ans,cnt)
print(ans)