#include <cstdio>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <functional>

using namespace std;
const int maxn=25;
int n,a,b[maxn],ans;

void gao(int x,int res,int c){
    if(c>=ans)return;
    if(!res){ ans=c; return; }
    if(x>=n)return;
    gao(x+1,res,c);
    gao(x+1,res%b[x],c+1);
}
void dit(){
    scanf("%d%d",&n,&a);
    for(int i=0;i<n;++i)scanf("%d",b+i);
    sort(b,b+n,greater<int>());
    ans=n+1; gao(0,a,0);
    if(ans>n)ans=-1;
    printf("%d\n",ans);
}
int main() {
    int t;scanf("%d",&t);while(t--)dit();
}