#include<bits/stdc++.h>
using namespace std;
using ll=long long;
using pii=pair<int,int>;

#define all(a) a.begin(),a.end()
#define pb push_back
#define sz(a) ((int)a.size())

const int maxn=5005;
int n,dp[maxn];
string s;
bool a[maxn][maxn];

signed main(){
    ios_base::sync_with_stdio(0),cin.tie(0);
    cin >> s; n=s.size();
    for(int i=0; i<=2*n-2; ++i){
        int l=i/2,r=i-l;
        while(l>=0&&r<n&&s[l]==s[r]) a[r][l]=1,l--,r++;
    }
    dp[0]=n+1;
    for(int i=0; i<n; ++i){
        dp[i+1]=-1;
        for(int j=0; j<=i; ++j) if(a[i][j]) dp[i+1]=max(dp[i+1],min(dp[j],i-j+1));
    }
    cout << dp[n] << "\n";
}