#273 mirror sentence
S=input()
for i in range(len(S)-3):
    if S[i]==S[i+2]:
        j=0
        c=2
        a=2
        while i-j>=0 and i+j<len(S)-2 and S[i-j]==S[i+2+j]:
            c+=2
            j+=1
        if c>a:
            a=c
print(a)