#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;
const int MOD = 1000000007;
#define op(x) (x&(-x))
#define trace1(x)                cerr << #x << ": " << x << endl;
#define trace2(x, y)             cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y, z)          cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": " << z << endl;
#define trace4(a, b, c, d)       cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << endl;
#define trace5(a, b, c, d, e)    cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << " | " << #e << ": " << e << endl;
#define trace6(a, b, c, d, e, f) cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << " | " << #e << ": " << e << " | " << #f << ": " << f << endl;
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define si(n) scanf("%d",&n)
#define s2i(x,y) scanf("%d %d",&x,&y);
#define s3i(x,y,z) scanf("%d %d %d",&x,&y,&z);
#define s4i(x,y,z,w) scanf("%d %d %d %d",&x,&y,&z,&w);
#define print(a,n) for(int i=0;i<n;i++) cout<<a[i]<<" "; cout<<endl;
#define print2d(a,n,m) for(int i=0;i<n;i++) {for(int j=0;j<m;j++) cout<<a[i][j]<<" "; cout<<endl;}

//FILE *fin = freopen("in","r",stdin);
//FILE *fout = freopen("out","w",stdout);
vector<pair<int,int> > v;

int main()
{
	int n,q;
	cin>>q;
	while(q--)
	{
		v.clear();
		cin>>n;
		int minx=INT_MAX,miny=INT_MAX,maxx=INT_MIN,maxy=INT_MIN;
		for(int i=0;i<n;i++)
		{
			int x,y;
			cin>>x>>y;
			minx = min(minx,x), miny = min(miny,y), maxx = max(maxx,x), maxy = max(maxy,y);
			v.push_back({x,y});
		}
		bool flag = true;
		for(int i=0;i<n;i++)
		{
			int x = v[i].first, y = v[i].second;
			if(x==minx||x==maxx||y==maxy||y==miny)
				continue;
			else
				flag = false;
		}
		if(flag) cout<<"YES"<<endl;
		else cout<<"NO"<<endl;
	}
	return 0;
}