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

int main(){
  int t;
  cin >> t;
  while (t--){
    ll n, k;
    cin >> n >> k;
    if (n >= k){
      cout << 0 << endl;
      continue;
    }
    ll x = k / n;
    ll p = x / 2, q = (x + 1) / 2;
    ll mx = p * (k - (n * p));
    mx = max(mx, q * (k - (n * q)));
    cout << mx << endl;
  }
}