#include <iostream>
#include <algorithm>

using namespace std;

long long ls[100000], rs[100000];

void solve() {
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> ls[i] >> rs[i];
    }
    int sl[n], sr[n];
    for (int i = 0; i < n; ++i) sl[i] = sr[i] = i;
    sort(sl, sl + n, [](const int& i1, const int& i2) {
        return ls[i1] < ls[i2];
    });
    sort(sr, sr + n, [](const int& i1, const int& i2) {
        return rs[i1] > rs[i2];
    });
    if (n == 1) {
        cout << 1 << endl;
        return;
    }
    long long res = (rs[sr[0]] - ls[sl[0]] + 1) * (rs[sr[0]] - ls[sl[0]]) / 2 - (ls[sl[1]] - ls[sl[0]]) * (ls[sl[1]] - ls[sl[0]] - 1) / 2 - (rs[sr[0]] - rs[sr[1]]) * (rs[sr[0]] - rs[sr[1]] - 1) / 2;
    if (sr[0] == sl[0]) {
        res -= (rs[sr[0]] - rs[sr[1]]) * (ls[sl[1]] - ls[sl[0]]);
    }
    cout << res << endl;
}

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

    return 0;
}