def solve():
    S="*"+input(); N=len(S)-1

    E=[[None for r in range(N+2)] for l in range(N+2)]
    for l in range(N+1,-1,-1):
        El=E[l]
        Ell=E[l+1] if l<N+1 else None
        for r in range(l,N+2):
            if r-l<=1:
                El[r]=True
            else:
                El[r]=(S[l]==S[r-1]) and Ell[r-1]

    inf=float("inf")
    DP=[-inf]*(N+1); DP[0]=inf
    for i in range(1,N+1):
        for j in range(1,i+1):
            if E[j][i+1]:
                DP[i]=max(DP[i], min(DP[j-1], i-j+1))
    return DP[N]

#==================================================
print(solve())