import java.io.*;
import java.util.*;

public class Solution {

    static class P{
        int x, y;
        
        public P(int a, int b){
            x=a;
            y=b;
        }
    }
    
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int t = in.nextInt();
        while(t-->0){
            int n = in.nextInt();
            P[] ps = new P[n];
            int minX=10000000;
            int minY=10000000;
            int maxX=-1000000;
            int maxY=-10000000;
            for(int i=0; i<n; i++){
                ps[i] = new P(in.nextInt(), in.nextInt());
                minX=Math.min(minX, ps[i].x);
                maxX=Math.max(maxX, ps[i].x);
                minY=Math.min(minY, ps[i].y);
                maxY=Math.max(maxY, ps[i].y);
            }
            boolean flag=true;
            for(int i=0; i<n; i++){
                if (ps[i].y==maxY || ps[i].y==minY){
                    continue;
                }
                if (ps[i].x==minX || ps[i].x==maxX){
                    continue;
                    
                }
                flag=false;
                break;
            }
            System.out.println(flag?"YES":"NO");
            
            
        }
    }
}