/*
 * Author: nskybytskyi
 * Time:   2022-01-07 16:20:00
 */

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

int main() {
  cin.tie(0)->sync_with_stdio(0);

  int t; cin >> t; while (t--) {
    int64_t n, m;
    cin >> n >> m;

    if (m <= n) {
      cout << m / 2 << "\n";
    } else {
      int64_t x = m - n;
      cout << (x * 1ll * (x + 1)) / 2 - 2 + m / 2 << "\n";
      // cout << (x * 1ll * (x + 5)) / 2 + m + 1 << "\n";
    }
  }

  return 0;
}