#include <bits/stdc++.h>
using namespace std;

const int N = 1e6+5;




void solve(){
    string s;
    cin >> s;
    int n = s.size();
    auto check = [=]( int len ){
        string k;
        for( int i = 0 ; i + len - 1 < n ; i ++ ){
            k = s.substr( i , len );
            for( int j = i+len ; j + len - 1 < n ; j ++ ){
                if( k == s.substr( j , len ) ) return k;
            }
        }
        k = "-1";
        return k;
    };

    int l = 1 , r = n , mid;
    string t , res;
    while( l <= r ){
        mid = ( l + r ) >> 1;
        t = check(mid);
        if( t == "-1" ) r = mid - 1;
        else res = t , l = mid + 1;
    }
    cout << res << "\n";
}

int32_t main(){
    int t ; cin >> t;
    while( t --> 0 ) solve();
}