#include<bits/stdc++.h>
using namespace std;
#define int long long
void solve() {
    int n;
    cin >> n;
    int k; cin >> k;
    int a[n + 1]; for(int i = 1; i <= n; i++) cin >> a[i];
    multiset<int> data;
    for(int i = 1; i <= n; i++) data.insert(a[i]);
    multiset<int, greater<int>> ms;
    int curr = k;
    int cnt = 0;
    while(!data.empty()) {
        while(1) {
            auto it = data.upper_bound(curr);
            if(it == data.begin()) {
                if(!ms.empty()) {
                    int temp = *ms.begin();
                    ms.erase(ms.begin());
                    curr += temp;
                    cnt++;
                }
                else {
                    cout << "-1\n";
                    return ;
                }
            }
            else {
                it--;
                int val = *it;
                data.erase(it);
                ms.insert(2 * val);
                curr -= val;
                break;
            }
        }
    }
    cout << cnt << "\n";
    /*sort(a + 1, a + n + 1);
    multiset<int, greater<int>> ms;
    int temp = k;
    int cnt = 0;
    for(int i = 1; i <= n; i++) {
        int total = 0;
        while(temp < a[i] and !ms.empty()) {
            int temp1 = *ms.begin();
            ms.erase(ms.begin());
            temp += temp1;
            cnt++;
        }
        if(temp < a[i]) {
            cout << "-1\n";
            return ;
        }
        ms.insert(a[i] * 2);
        temp -= a[i];
    }*/
}
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int t;
    cin >> t;
    while(t--) {
        solve();
    }
}