#include <bits/stdc++.h>
#include <cassert>

using namespace std;
#define int long long
#define all(x) x.begin(), x.end()
#define pb push_back
#define ll long long
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<ii>
#define vvi vector<vi>
#define vll vector<long long>
#define fi first
#define se second
void test_case() {
   int n;
   ll x;
   cin >> n >> x;

    ll sum = 0;
    multiset<int> S;
    for (int i = 0; i < n; i ++) {
        int a;
        cin >> a;
        S.insert(a);
        sum += a;
    }

    int res = 0;
    while (x < sum && S.size() > 0) {
        auto it = S.upper_bound(x);
        if (it == S.begin()) { 
            cout << -1 << '\n';
            return;
        }

        it --;
        int y = *it;
        S.erase(it);
        sum -= y;
        x += y;
        res ++;
    }

    cout << res << '\n';
}
int32_t main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int tc = 1;
    cin >> tc;
    while(tc--) {
        test_case();
    }
    return 0;
}