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 xo=0,yo=0;
        int x1=0,y1=0;
        int co=1;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(co==1)
                {
             x1=x;
            y1=y;
                co=2;
            }
           if(x==x1)
                xo++;
            if(y==y1)
                yo++;
                
        }
        if(xo==n||yo==n)
            System.out.println("YES");
        else
            System.out.println("NO");
            
    }
}