#include <iostream>
#include <algorithm>

using namespace std;

void solve() {
    int n;
    cin >> n;
    pair<int,int> ps[n];
    for (int i = 0; i < n; ++i) {
        cin >> ps[i].first >> ps[i].second;
    }
    sort(ps, ps + n);
    if (n == 1) {
        cout << 1 << endl;
        return;
    }
    long long l1 = ps[0].first;
    long long l2 = ps[1].first;
    sort(ps, ps + n, [](const pair<int,int>& p1, const pair<int,int>& p2) {
        return p1.second > p2.second;
    });
    long long r1 = ps[0].second;
    long long r2 = ps[1].second;
    long long res = (r1 - l1 + 1) * (r1 - l1) / 2 - (l2 - l1) * (l2 - l1 - 1) / 2 - (r1 - r2) * (r1 - r2 - 1) / 2;
    cout << res << endl;
}

int main() {
    int t;
    cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}