#include <bits/stdc++.h>
using namespace std;

using int64 = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T;
    cin >> T;
    while (T--) {
        int N;
        int64 K;
        cin >> N >> K;

        vector<int64> A(N), B(N), C(N), D(N);
        for (int i = 0; i < N; i++) cin >> A[i];
        for (int i = 0; i < N; i++) cin >> B[i];
        for (int i = 0; i < N; i++) cin >> C[i];
        for (int i = 0; i < N; i++) cin >> D[i];

        map<int64, int64> mp;
        int64 total = 0;
        int64 ans = 0;

        for (int i = N - 1; i >= 0; i--) {
            mp[C[i]] += D[i];
            total += D[i];

            int64 buy = B[i];
            while (buy > 0 && !mp.empty()) {
                auto it = prev(mp.end());
                int64 v = it->first;
                int64 cnt = it->second;
                if (v <= A[i]) break;

                int64 take = min(buy, cnt);
                ans += take * (v - A[i]);

                it->second -= take;
                if (it->second == 0) {
                    mp.erase(it);
                }
                mp[A[i]] += take;
                buy -= take;
            }

            while (total > K) {
                auto it = mp.begin();
                int64 take = min(total - K, it->second);
                it->second -= take;
                total -= take;
                if (it->second == 0) {
                    mp.erase(it);
                }
            }
        }

        cout << (long long)ans << '\n';
    }

    return 0;
}