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 xchange = false;
        boolean ychange = false;
        int xpre = in.nextInt();
        int ypre = in.nextInt();
        for(int a0 = 0; a0 < n-1; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(x != xpre){
                xchange = true;
            }
            if(y != ypre){
                ychange = true;
            }
        }
        
        if(!xchange || !ychange){
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}