s=input();n=len(s);ans=0
for i in range(n):
    c=1;j=1
    while 0<=i-j and i+j<n:
        if s[i-j]==s[i+j]:
            c+=2
        j+=1
    ans=max(ans,c)
for i in range(n-1):
    if s[i]!=s[i+1]:continue
    c=2;j=1
    while 0<=i-j and i+1+j<n:
        if s[i-j]==s[i+1+j]:
            c+=2
        j+=1
    ans=max(ans,c)
print(ans)