#include<bits/stdc++.h>

using namespace std;

using namespace std;

const int N = 30;

int a[N];
int n;
vector<string> st;

void solve() {
    string s;
    cin >> s;
    st.clear();
    for (int i = 2; i <= s.size(); i++) {
        for (int j = 0; j + i - 1 < s.size(); j++) {
            string str = s.substr(j, i);
            //cout << str << s.find(str, j + 1)<<endl;
            if (s.find(str, j + i) != s.npos)st.push_back(str);
        }
    }
    //cout << st.size() << endl;
    int ans = 0;
    string sans;
    for (auto i: st) {
        if (ans < i.size()){
            ans = i.size();
            sans=i;
        }
        //cout << i << endl;
    }
    cout<<sans<<endl;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int h_h;
    cin>>h_h;
    cin.get();
    while(h_h--)solve();
    return 0;
}