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 k=0;
        int ax[]=new int[n];
        int ay[]=new int[n];
        for(int i = 0; i < n; i++){
            ax[i] = in.nextInt();
            ay[i] = in.nextInt();
        }
        if(ax[0]==ax[1]){
            for(int i=0;i<n;i++){
                if(ax[i]!=ax[0]){
                    k=1;
                    break;
                }
                    
            }
        }
        if(ay[0]==ay[1]){
            for(int i=0;i<n;i++){
                if(ay[i]!=ay[0]){
                    k=1;
                    break;
                }
                    
            }
        }
            if(k==0)
                System.out.println("YES");
            else
                System.out.println("NO");
    }
}