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

#define int long long

bool overlap(pair<int, int> a, pair<int, int> b) {
	auto [l1, r1] = a;
	auto [l2, r2] = b;

	if (l1 > r2) return 0;
	if (l2 > r1) return 0;
	return 1;
}

void solve() {
	int n; cin >> n;
	vector<pair<int, int>> p;
	for (int i = 0; i < n; i++) {
		int l, r; cin >> l >> r;
		p.emplace_back(l, 0);
		p.emplace_back(r, 1);
	}
	sort(p.begin(), p.end());

	int ans = 0;
	int prv = 1;
	for (auto [x, c]: p) {
		if (c != (prv^1)) {
			cout << ans << '\n';
			return;
		} else {
			prv ^= 1;
			ans += prv;
		}
	}
	cout << ans << '\n';
}

signed main() {
	ios::sync_with_stdio(0); cin.tie(0);
	
	int t; cin >> t;
	while (t--) {
		solve();
	}

	return 0;
}