#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
      int T;
      cin >> T;
      int n, a, b[25], i, cnt;
      while(T--) {
            int Min = 50;
            bool tag = false;
            cin >>n >> a;
            for(int i = 0; i < n; ++i)
                  cin >> b[i];
            sort(b, b+n);
            for(i = n-1; i >= 0; --i) {
                  if(a >= b[i])
                        break;
            }
            if(i == 0) {
                  if(a % b[0] == 0)
                        cout << 1 << endl;
                  else
                        cout << -1 << endl;
            } else {
                  for(int j = 1; j < (1 << (i+1)); ++j) {
                        int tmp = a;
                        cnt = 0;
                        for(int k = i; k >= 0 ; --k) {
                              if((1 << k) & j) {
                                    tmp %= b[k];
                                    cnt++;
                                    //cout << j << " " <<tmp << " " << b[k] << " "<<cnt << endl;;
                              }
                        }
                        if(tmp == 0) {
                              Min = min(Min, cnt);
                              tag = true;
                        }
                  }
                  if(tag)
                        cout << Min << endl;
                  else
                        cout << -1 << endl;
            }
      }
      return 0;
}