#include <string.h>
#include <algorithm>
#include <array>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while(t--) {
        int n,m;
        cin >> n >> m;
        vector<int>l(n),r(n);
        long long sum1 = 0,sum2 = 0;
        for(int i = 0; i < n; i++) {
            cin >> l[i];
            sum1 += l[i];
        }
        for(int i = 0; i < n; i++) {
            cin >> r[i];
            sum2 += r[i];
        }
        if(sum1 <= m && m <= sum2) {
            int L = 0,R = 1001001001;
            while(L+1 < R) {
                int mid = (L+R)/2;
                long long sum = 0;
                for(int i = 0; i < n; i++) {
                    sum += max(l[i],min(mid,r[i]));
                }
                if(sum >= m) {
                    R = mid;
                }
                else {
                    L = mid;
                }
            }
            long long res = 0;
            vector<int>tmp(n);
            for(int i = 0; i < n; i++) {
                tmp[i] = max(l[i],min(L,r[i]));
                res += tmp[i];
            }
            long long ans = 0;
            for(int i = 0; i < n; i++) {
                if(res < m && tmp[i] == L) {
                    res++;
                    tmp[i]++;
                }
                ans += 1ll*tmp[i]*(m-tmp[i]);
            }
            cout << ans/2 << "\n";
        }
        else {
            cout << -1 << "\n";
        }
    }
}