S=input()
a=1
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
i=0
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
        #    print(S[i-j])
        if c>a:
            a=c
    i +=1
if a==len (S):
    if a==2:
        a=1
    else:
        a-=2
print(a)