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[]xval = new int[n];
        int[]yval = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            xval[a0]= x;
            int y = in.nextInt();
            yval[a0]= y;
        }
        
        boolean allX = true;
       boolean allY= true;
        
        int xcheck= xval[0];
        for(int i=1;i<xval.length;i++){
            if(xval[i]!=xcheck){
                allX=false;
                break;
            }
        }
        
        if(!allX){
                 int ycheck= yval[0];
                 for(int i=1;i<yval.length;i++){
                 if(yval[i]!=xcheck){
                    allY=false;
                    break;
                }
            }
        }
        
        if(!allX && !allY )
            System.out.println("NO");
        else
             System.out.println("YES");
        
    }
}