// #include C {
#include<cstring>
#include<cassert>
#include<cstdio>
#include<cctype>
#include<cmath>
// }

// #include C++ {
#include<functional>
#include<algorithm>
#include<iostream>
#include<numeric>
#include<vector>
#include<string>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<list>
#include<map>
#include<set>
// }
using namespace std;
// #typedef {
typedef long long int64;
typedef unsigned long long uint64;
typedef pair <int, int> PII;
typedef pair <char, char> PCC;
typedef pair <int64, int64> PLL;
typedef pair <double, double> PDD;
// }

// #parameter{
#ifdef DEBUG_MODE

#define TYPE decltype
#define RF(filename) {freopen((filename), "r", stdin);}
#define WF(filename) {freopen((filename), "w", stdout);}
#define DEBUG printf

#else

#define TYPE __typeof
#define RF(filename) {;}
#define WF(filename) {;}
#define DEBUG(...)

#endif

// #define {
#define SZ(a) ((int)(a).size())
#define X first
#define Y second
#define MP make_pair
#define L(x) ((x)<<1)
#define R(x) ((x)<<1 | 1)
#define max3(x, y, z) (max(max((x), (y)), (z)))
#define min3(x, y, z) (min(min((x), (y)), (z)))
#define BIT(x, i) (((x) >> (i)) & 1)
#define ALL(it) (it).begin(), (it).end()
#define FILL(__space, __val) memset(__space, __val, sizeof(__space))
#define MOVE(__spaceTo, __spaceFrom) memmove(__spaceTo, __spaceFrom, sizeof(__spaceTo))
#define FOR(it, c) for( TYPE((c).begin()) it = (c).begin(); it != (c).end(); it++)
/////////////////////////////////////////////////////////////
const double PI = acos(-1.0);
const double EPS = 1e-6;

#define MAX_N 25
#define MAX_M 800005
#define MOD (int)(1e9+7)
#define INF ((1 << 30) - 1)
#define BINF ((1LL << 62) - 1LL)
#define NONE -1
#define NIL 0
// }

/////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////
int main(){
    RF("input.txt");
//    WF("output.txt");

    int T;
    scanf("%d", &T);
    while (T--){
        int n, a;
        scanf("%d %d", &n, &a);
        int b[MAX_N];
        for (int i = 0; i < n; i++)
            scanf("%d", b + i);
        sort(b, b + n);
        reverse(b, b + n);
        const int N = 1 << n;
        int res = INF;
        for (int st = 0; st < N; st++){
            int one = 0;
            for (int tmp = st; tmp > 0; tmp >>= 1) if (tmp & 1) one++;
            if (one >= res) continue;
            int now = a;
            for (int k = 0, tmp = st; k < n; k++, tmp >>= 1)
                if (tmp & 1) now %= b[k];
            if (now == 0)
                res = one;
        }
        if (res == INF)
            puts("-1");
        else
            printf("%d\n", res);
    }

    return 0;
}