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

    E=[[r-l<=1 for r in range(N+2)] for l in range(N+2)]
    for k in range(1,N+1):
        for l in range(N-k+2):
            E[l][l+k]=(S[l]==S[l+k-1]) and E[l+1][l+k-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())