S=input()
a=0
i=0
while i < len(S)-2:
    if S[i]==S[i+2]:
        j=1
        c=3
        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
    i+=1
while i<len(S)-1:
    if S[i]==S[i+1]:
        j=1
        c=2
        while i-j>=0 and i+j<len(S)-1 and S[i-j]==S[i+1+j]:
            c+=2
            j+=1
        if c>a:
            a=c
    i +=1
print(a)