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 in = new Scanner(System.in);
        int n = in.nextInt();
        int vertical=1,horizontal=1;
        int x[]=new int[n];
        int y[]=new int[n];
        for(int i = 0; i < n; i++)
        {
             x[i] = in.nextInt();
             y[i] = in.nextInt();
        }
        
        if(x[1]==x[0])
            {
        for(int i=2;i<n;i++)
            {
            if(x[i]!=x[0])
                {
                vertical=0;
                break;
                }
            }
            if(vertical==1)
                System.out.println("YES");
            else if(vertical==0)
                  System.out.println("NO");
        }
        
        else if(y[1]==y[0])
        {
            for(int i=2;i<n;i++)
            {
            if(y[i]!=y[0])
                {
                horizontal=0;
                break;
                }
            }
            if(horizontal==1)
                System.out.println("YES");
            else if(horizontal==0)
                  System.out.println("NO");
        }
        else
            {
            System.out.println("NO");
        }
        
       
    }
}