import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner s=new Scanner(System.in);
        int q=s.nextInt();
        int xArr[];
        int yArr[];
        for(int t=0;t<q;t++)
            {
            int n=s.nextInt();
            xArr=new int[n];
            yArr=new int[n];
            int maxX,minX,maxY,minY;
            for(int i=0;i<n;i++)
                {
                xArr[i]=s.nextInt();
                yArr[i]=s.nextInt();
            }
            maxX=xArr[0];
            maxY=yArr[0];
            minX=xArr[0];
            minY=yArr[0];
            for(int i=1;i<n;i++)
                {
                if(maxX<xArr[i]) maxX=xArr[i];
                if(minX>xArr[i]) minX=xArr[i];
                if(maxY<yArr[i]) maxY=yArr[i];
                if(minY>yArr[i]) minY=yArr[i];
            }
            int flag=0;
            for(int i=0;i<n;i++)
                {
                if(xArr[i]!=minX && xArr[i]!=maxX && yArr[i]!=minY && yArr[i]!=maxY) flag=1;
            }
                if(flag==0)
                    {
                    System.out.println("YES");
                }
                else
                    {
                    System.out.println("NO");
                }
        }
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    }
}