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

#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...)
#endif

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    int T;
    cin >> T;
    while (T--) {
        int K;
        string S;
        cin >> K >> S;
        int N = ssize(S);
        if (K > N) {
            cout << string(N, S.front()) << "\n";
        } else {
            while (K--) {
                S.insert(S.begin(), S.front());
                S.pop_back();
            }
            cout << S << "\n";
        }
    }
}