import java.io.*;
import java.util.*;
public final class hack_b
{
    static BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
	static FastScanner sc=new FastScanner(br);
    static PrintWriter out=new PrintWriter(System.out);
	
    public static void main(String args[]) throws Exception
    {
		int t=sc.nextInt();
		while(t>0)
		{
			int n=sc.nextInt();Pair[] a=new Pair[n];int min_x=Integer.MAX_VALUE,min_y=Integer.MAX_VALUE,max_x=Integer.MIN_VALUE,max_y=Integer.MIN_VALUE;
			for(int i=0;i<n;i++)
			{
				a[i]=new Pair(sc.nextInt(),sc.nextInt());min_x=Math.min(min_x,a[i].x);min_y=Math.min(min_y,a[i].y);max_x=Math.max(max_x,a[i].x);max_y=Math.max(max_y,a[i].y);
			}
			boolean ans=true;
			for(int i=0;i<n;i++)			
			{
				if((a[i].x!=max_x && a[i].x!=min_x) && (a[i].y!=min_y && a[i].y!=max_y))
				{
					ans=false;break;
				}
			}
			out.println(ans?"YES":"NO");t--;
		}
		out.close();
    }
}
class Pair
{
	int x,y;
	public Pair(int x,int y)
	{
		this.x=x;this.y=y;
	}
}
class FastScanner
{
    BufferedReader in;
    StringTokenizer st;

    public FastScanner(BufferedReader in) {
        this.in = in;
    }
	
    public String nextToken() throws Exception {
        while (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(in.readLine());
        }
        return st.nextToken();
    }
	
	public String next() throws Exception {
		return nextToken().toString();
	}
	
    public int nextInt() throws Exception {
        return Integer.parseInt(nextToken());
    }

    public long nextLong() throws Exception {
        return Long.parseLong(nextToken());
    }

    public double nextDouble() throws Exception {
        return Double.parseDouble(nextToken());
    }
}