/*input
1
*/


#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
vector<pair<int,int> >p;
bool sorted(const pair<int,int>&a, const pair<int,int>&b)
{
	if(a.second<b.second)
		return true;
	return false;
} 
int main()
{
	int t;
	cin>>t;
	while(t--)
	{
		int n;
        p.clear();
		cin>>n;
		for(int i=0;i<n;i++)
		{
			int a,b;
			cin>>a>>b;
			p.push_back(make_pair(a,b));

		}
		sort(p.begin(),p.end());
		int x0 = p[0].first;
		int x1 = p[n-1].first;
		sort(p.begin(),p.end(),sorted);
		int y0 = p[0].second;
		int y1 = p[n-1].second;
		int i=0;
		for( i=0;i<n;i++)
		{
			pair<int,int>te = p[i];
			if(te.first==x0||te.first==x1||te.second==y0||te.second==y1)
				continue;
			else
				break;
		}
		if(i==n)
			cout<<"YES"<<endl;
		else
			cout<<"NO"<<endl;
	}

	return 0;
}