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

using isize = size_t;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
using f64 = long double;
using p2 = pair<i64, i64>;
using el = tuple<i64, i64, i64>;
using mint = atcoder::modint998244353;

void _main();
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(18);
  _main();
}

i64 pow(i64 x, i64 n) {
  i64 res = 1;
  i64 t = x;
  while (n > 0) {
    if (n & 1) res *= t;
    t *= t;
    n >>= 1;
  }
  return res;
}
i64 pow(i64 x, i64 n, i64 m) {
  i64 res = 1;
  i64 t = x % m;
  while (n > 0) {
    if (n & 1) res = res * t % m;
    t = t * t % m;
    n >>= 1;
  }
  return res;
}

void _main() {
  i64 ttt;
  cin >> ttt;
  for (;ttt--;) {
    i64 k;
    cin >> k;
    string s;
    cin >> s;
    if (k >= s.size()) {
      cout << string(s.size(), s[0]) << "\n";
    } else {
      while (k > 0) {
        string t;
        t += s[0];
        t += s;
        t.pop_back();
        swap(s, t);
        k--;
      }
      cout << s << "\n";
    }
  }
}