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();
        boolean tx=true;boolean ty=true;
        int x = in.nextInt();
        int y = in.nextInt();
        for(int a0 = 1; a0 < n; a0++){
            int x1 = in.nextInt();
            int y1 = in.nextInt();
            if(tx&&x==x1){
                x=x1;
            }else{
                tx=false;
            }
            if(ty&&y==y1){
                y=y1;
            }else{
                ty=false;
            }
        }
        if(ty||tx){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
}