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

class Point {
    int xCor;
    int yCor;
    
    public Point(int xCor, int yCor)
        {
        this.xCor = xCor;
        this.yCor = yCor;
    }
       public int getxCor() {
		return xCor;
	}

	public int getyCor() {
		return yCor;
	}
    
}
 class Distance {
	Point p1,p2;
	public Distance(Point p1, Point p2) {
		this.p1=p1;
		this.p2=p2;
	}
	public int calPerpendicular()
	{
		int d = p1.getyCor()*p2.getyCor()+ p1.getxCor()*p2.getxCor();
		return d;
	}

}
public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner sc = new Scanner(System.in);
        int q = sc.nextInt();
        while(q--!=0) {
            {
        int r = sc.nextInt();
        Point[] points = new Point[r];
        for( int i=0;i<q;i++)
            {
            int m = sc.nextInt();
                int n = sc.nextInt();
            points[i] = new Point(m,n);
        }
        Distance d ;
        int a=0;
        for(int i=0 ;i<q;i++)
            {
            for(int j=0 ;j<q;j++)
            {
                d = new Distance(points[i],points[j]);
                if(d.calPerpendicular()==0)
                    {
                    a++;
                    
                }
            
            }
        }
        if(a!=r)
        System.out.println("YES");
                else
                    System.out.println("NO");
 }
}
}
}