#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef double db;
#define all(x) (x).begin(), (x).end()

const ll MAXN = 1e9, MINN = -1e9;
const ld pi = 3.14159265358979323846264338327950288;

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
}

ll gcd(ll a, ll b) {
    while (b) {
        a %= b;
        swap(a, b);
    }
    return a;
}

void solve() {
    ll n, m;
    cin >> n >> m;
    vector<ll> a(n);
    vector<ll> b(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) cin >> b[i];
    vector<ll> one, two;
    for (int i = 0; i < n; i++) {
        if (b[i] == 1) {
            one.push_back(a[i]);
        } else {
            two.push_back(a[i]);
        }
    }
    sort(all(one));
    sort(all(two));
    one.push_back(0);
    two.push_back(0);
    reverse(all(one));
    reverse(all(two));

    vector<ll> pref1(one.size()), pref2(two.size());

    for (int i = 1; i < one.size(); i++) {
        pref1[i] = pref1[i - 1] + one[i];
    }
    for (int i = 1; i < two.size(); i++) {
        pref2[i] = pref2[i - 1] + two[i];
    }
    ll ans = 1e18;
//    for (auto i : one) cout << i << " ";
//    cout << '\n';
//    for (auto i : two) cout << i << " ";
//    cout << "\n";
    for (int i = 0; i < one.size(); i++) {
        int now = i;
        ll find = m - pref1[i];
        auto it = lower_bound(all(pref2), find);
        if (it == pref2.end()) continue;
        ll cnt = it - pref2.begin();
        ll cur = now + cnt * 2;
        ans = min(ans, cur);
    }
    for (int i = 0; i < two.size(); i++) {
        int now = i;
        ll find = m - pref2[i];
        auto it = lower_bound(all(pref1), find);
        if (it == pref1.end()) continue;
        ll cnt = it - pref1.begin();
        ll cur = cnt + now * 2;
        ans = min(ans, cur);
    }
    if (ans == 1e18) {
        cout << -1 << "\n";
    } else {
        cout << ans << "\n";
    }
}

int main() {
    ll t = 1;
    fastio();
    cin >> t;
    while (t--) { solve(); }
    return 0;
}