#include<bits/stdc++.h>
//using namespace std;
using std::cin;
using std::cout;
void solve() {
	int n;
	cin >> n;
	std::vector<int> fa(n + 2);
	std::iota(fa.begin(), fa.end(), 0);
	auto find = [&](auto find, int x) -> int {
		return fa[x] == x ? x : fa[x] = find(find, fa[x]);
	};
	int ok = 1;
	for(int i = 1; i <= n; i++) {
		int l, r;
		cin >> l >> r;
		++ r;
		if(find(find, l) == find(find, r)) {
			ok = 0;
			continue;
		}
		fa[find(find, l)] = find(find, r);
	}
	int cnt = 0;
	for(int i = 0; i <= n; i++) cnt += (find(find, i) == i);
	if(!ok || cnt != 1) return cout << 0 << '\n', void();
	else return cout << 1 << '\n', void();
}
int main() 
{
	std::ios::sync_with_stdio(0);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int t = 1;
	cin >> t;
	while(t--) solve();
	return 0;
}