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 x0 = in.nextInt();
        int y0 = in.nextInt();
        boolean horizontal = true;
        boolean vertical = true;
        for(int a0 = 0; a0 < n-1; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (y != y0) {
                vertical = false;
            }
            if (x != x0) {
                horizontal = false;
            }
        }
        
        if (horizontal || vertical) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
       
        in.close();
    }
}