iiitv/ChefLib

// Code by Piyush
#include <bits/stdc++.h>
#define endl "\n"
using namespace std;

int main() {

    std::ios::sync_with_stdio(false);
    int testCases;
    cin >> testCases;
    while (testCases--) {
        int n;
        cin >> n;
        int a[n];
        for (int i = 0; i < n; i++)
            cin >> a[i];
        for (int i = 0; i < n; i++)
            cout << a[i];
        cout << endl;
    }
    return 0;
}