#include <cstring>
#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <cmath>
#include <map>
#include <string>
#include <queue>
#include <bitset>
using namespace std;

int T;
int n,a;
const int maxn = (1 << 20) - 1;
int arr[25];
int cmp(int x,int y)
{
    return y < x;
}
int getOnes(int x)
{
    int nums = 0;
    while(x > 0)
    {
        if(x & 1) nums ++;
        x >>= 1;
    }
    return nums;
}

int fun(int x)
{
    int tmp = a;
    int pos = 0;
    int ans = 0;
    while(x > 0 && pos < n)
    {
        if(x & 1)
        {
            tmp %= arr[pos];
            ans ++;
        }

        x >>= 1;
        pos ++;
    }
    if(tmp == 0) return ans;
    else return -1;
}
int main()
{
    //freopen("in.txt","r",stdin);
    scanf("%d",&T);
    while(T --)
    {
        scanf("%d%d",&n,&a);
        for(int i=0;i<n;i++)
        {
            scanf("%d",&arr[i]);
        }
        sort(arr,arr+n,cmp);
        int mins = 0x3f3f3f3f;
        for(int i=1;i<=maxn;i++)
        {
            if(getOnes(i) >= mins) continue;
            int res = fun(i);
            if(res > 0 && res < mins )
            {
                mins = res;
            }
        }
        if(mins != 0x3f3f3f3f)
        {
            printf("%d\n",mins);
        }
        else{
            printf("-1\n");
        }
    }
    //while(1);
    return 0;
}