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) {
        int firx=0,firy=0,flagx=0,flagy=0;
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(a0==0)
                {
                firx = x;
                firy = y;
            }
            else
                {
                if(x==firx)
                    {
                    
                }
                else{
                    flagx=1;
                }
                
                if(y==firy)
                    {
                    
                }
                else{
                    flagy=1;
                }
            }
        }
        if(flagx==0 || flagy==0)
            {
            System.out.println("YES");
        }
        else{
            System.out.println("NO");
        }
    }
}