S = input().strip()
ans = ""
for i in range(len(S)-1):
    for j in range(i+1,len(S)+1):
        if i==0 and j==len(S):continue
        a = S[i:j]
        b = a[::-1]
        if a==b and len(a)>len(ans):
            ans = a
print(len(ans))