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 x = in.nextInt();
        int y = in.nextInt();
        boolean rX = true;
        boolean rY = true;
        for(int a0 = 1; a0 < n; a0++){
            int x1 = in.nextInt();
            int y1 = in.nextInt();
            if (x != x1) {
                rX = false;
            }
            if (y != y1) {
                rY = false;
            }
            if (!rX && !rY) {
                break;
            }
        }
        System.out.println((rX || rY) ? "YES" : "NO");
    }
}