/*
coded by @just_code21
© to Prakhar Srivastava
*/
#include<bits/stdc++.h>
#define M 1000000007
#define INF 1000000007
#define MAX 100005
#define ull unsigned long long
#define ll long long int
#define bitcount(x) __builtin_popcount(x)
#define pii pair<int,int>
#define pb(x) push_back(x)
#define mp(a,b) make_pair(a,b)
#define F(i,a,n) for(int i=(a);i<(n);++i)
#define FF(i,j,k,in) for(int i=j;i<k;i+=in)
#define REP(i,a,n) for(i=(a);i<(n);++i)
#define FD(i,a,n) for(int i=(a);i>=(n);--i)
#define FE(it,x) for(it=x.begin();it!=x.end();++it)
#define V(x) vector<x>
#define S(x) scanf("%d",&x)
#define SL(x) scanf("%lld",&x)
#define SD(x) scanf("%lf",&x)
#define SC(x) scanf(" %c",&x)
#define SS(x) scanf("%s",&x)
#define MEM(x,i) memset(x,i,sizeof(x))
#define debug(i,sz,x) F(i,0,sz){cout<<x[i]<<" ";}cout<<endl
#define x first
#define y second

using namespace std;

int main()
{
	//ifstream fin("input.txt");
	int q;
	S(q);
	while(q--)
	{
		int n;
		S(n);
		int x=M,y=M,mx=-M,my=-M;
		pii arr[n];
		F(i,0,n)
		{
			S(arr[i].x),S(arr[i].y);
			x=min(x,arr[i].x);
			mx=max(mx,arr[i].x);
			y=min(y,arr[i].y);
			my=max(my,arr[i].y);
		}
		int counter=0;
		F(i,0,n)
		{
			if(arr[i].x>=x && arr[i].x<=mx && (arr[i].y==y||arr[i].y==my))
				counter++;
			else if(arr[i].y>=y && arr[i].y<=my && (arr[i].x==x||arr[i].x==mx))
				counter++;
		}
		if(counter==n)
			printf("YES\n");
		else
			printf("NO\n");
	}

	return 0;
}
/*

*/