#include <iostream> #include <string>

using namespace std;

void print_many_times(const int count, const string word) { for (int i = 0; i < word.size(); ++i) { for (int j = 0; j < count; ++j) cout << word[i]; } cout << "\n"; }

int main() { cin.tie(nullptr); ios_base::sync_with_stdio(false);

int T;
cin >> T;

for (int test_case = 0; test_case < T; ++test_case) {
	int re_num;
	string word;
	cin >> re_num >> word;

	print_many_times(re_num, word);
}

return 0;

}