#include <bits/stdc++.h>
using namespace std;
int main(){
  int T;
  cin >> T;
  for (int i = 0; i < T; i++){
    int n, m;
    cin >> n >> m;
    vector<int> L(n);
    for (int j = 0; j < n; j++){
      cin >> L[j];
    }
    vector<int> R(n);
    for (int j = 0; j < n; j++){
      cin >> R[j];
    }
    long long SL = 0, SR = 0;
    for (int j = 0; j < n; j++){
      SL += L[j];
      SR += R[j];
    }
    if (!(SL <= m && m <= SR)){
      cout << -1 << endl;
    } else {
      int tv = -1, fv = 1000000001;
      int cnt = 0;
      while (fv - tv > 1){
        int mid = (tv + fv) / 2;
        long long sum = 0;
        for (int j = 0; j < n; j++){
          sum += min(R[j], max(L[j], mid));
        }
        if (sum <= m){
          tv = mid;
          cnt = m - sum;
        } else {
          fv = mid;
        }
      }
      vector<int> C(n);
      for (int j = 0; j < n; j++){
        C[j] = min(R[j], max(L[j], tv));
      }
      for (int j = 0; j < n; j++){
        if (C[j] == tv && R[j] > tv && cnt > 0){
          C[j]++;
          cnt--;
        }
      }
      long long ans = (long long) m * (m - 1) / 2;
      for (int j = 0; j < n; j++){
        ans -= (long long) C[j] * (C[j] - 1) / 2;
      }
      cout << ans << endl;
    }
  }
}