#include "bits/stdc++.h"
#include <unordered_set>
#include <unordered_map>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
using t4 = tuple<ll, ll, ll, ll>;

int Z, N, K;
ll arr[220000];

int main() {
	cin >> Z;
	while (Z--) {
		cin >> N >> K;
		for (int i = 0; i < N; i++) cin >> arr[i];
		multiset<ll> st;
		ll sum = 0, k = K;
		for (int i = 0; i < N; i++) st.insert(arr[i]), sum += arr[i];
		int ans = 0;
		while (st.size() && sum > k) {
			auto iter = st.lower_bound(k);
			if (iter == st.end()) iter = prev(iter);
			if (*iter > k) {
				if (iter != st.begin()) iter = prev(iter);
				else break;
			}
			if (*iter > k) break;

			k += *iter;
			sum -= *iter;
			st.erase(iter);
			ans++;
		}
		if (sum > k) cout << -1 << '\n';
		else cout << ans << '\n';
	}
}