#include <bits/stdc++.h>
using namespace std;
void solve() {
  int N, M;
  cin >> N >> M;
  vector<long long> L(N), R(N);
  for(int i = 0; i < N; i++) {
    cin >> L[i];
  }
  for(int i = 0; i < N; i++) {
    cin >> R[i];
  }
  long long low = accumulate(L.begin(), L.end(), (long long) 0);
  if(!(low<= (long long) M && (long long) M <= accumulate(R.begin(), R.end(), (long long) 0))) {
    cout << "-1\n";
    return;
  }
  if(N == 1) {
    cout << "0\n";
    return;
  }
  long long ALL = (long long) M * M;
  long long ok = 1000000000, ng = *min_element(L.begin(), L.end()) - 1;
  while(abs(ok - ng) > 1) {
    long long mid = (ok + ng) >> 1;
    long long S = 0;
    for(int i = 0; i < N; i++) {
      if(mid >= L[i]) {
        S += min(mid, R[i]) - L[i];
      }
    }
    if(low + S >= M) {
      ok = mid;
    } else {
      ng = mid;
    }
  }
  vector<long long> T(N);
  vector<int> id;
  for(int i = 0; i < N; i++) {
    if(R[i] <= ok) {
      T[i] = R[i];
    } else if(L[i] >= ok) {
      T[i] = L[i];
    } else {
      T[i] = ok;
      id.emplace_back(i);
    }
  }
  long long S = accumulate(T.begin(), T.end(), (long long) 0);
  if(S > M) {
    for(int i = 0; i < S - M; i++) {
      T[id[i]]--;
    }
  } else if(M > S) {
    for(int i = 0; i < M - S; i++) {
      T[id[i]]++;
    }
  }
  assert(accumulate(T.begin(), T.end(), (long long) 0) == M);
  for(int i = 0; i < N; i++) {
    ALL -= T[i] * T[i];
  }
  assert(ALL % 2 == 0);
  cout << ALL / 2 << '\n';
}
int main() {
  cin.tie(0); cout.tie(0);
  ios::sync_with_stdio(false);
  int T;
  cin >> T;
  while(T--) {
    solve();
  }
  return 0;
}