/* -*- coding: utf-8 -*-
 *
 * 3274.cc:  No.3274 Arithmetic Right Shift - yukicoder
 */

#include<cstdio>
#include<cstring>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 64;

/* typedef */

/* global variables */

char s[MAX_N + 4];

/* subroutines */

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int k;
    scanf("%d%s", &k, s);
    int n = strlen(s);
    
    k = min(k, n - 1);
    for (int i = n - 1; i >= 1; i--) s[i] = s[max(0, i - k)];

    puts(s);
  }

  return 0;
}