//#pragma comment(linker,"/STACK:102400000,102400000")
#include<stdio.h>
#include<iostream>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<string>
#define ll long long
#define db double
#define PB push_back
#define lson k<<1
#define rson k<<1|1
using namespace std;

const int N = 25;
const int M = 1000006;
int r, b[N], n;

void dfs(int a, int k)
{
    if(k + 1 >= r) return;
    for(int i = 0; i < n; i++)
    {
        if(a % b[i] == 0)
        {
            r = min(r, k + 1);
            return;
        }
        else if(a > b[i])
        {
            dfs(a % b[i], k + 1);
        }
    }
}

int main()
{
#ifdef PKWV
//    freopen("in.in","r",stdin);
#endif // PKWV
    int T;
    scanf("%d", &T);
    while(T--)
    {
        int a;
        scanf("%d%d", &n, &a);
        for(int i = 0; i < n; i++)
        {
            scanf("%d", &b[i]);
        }
        r = 30;
        dfs(a, 0);
        if(r == 30) printf("%d\n", -1);
        else printf("%d\n", r);
    }
    return 0;
}