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 sameX = true;
        boolean sameY = true;
        for(int a0 = 0; a0 < n-1; a0++){
            int x1 = in.nextInt();
            int y1 = in.nextInt();
            if (x1 != x) sameX = false;
            if (y1 != y) sameY = false;
        }
        String ans = (sameX || sameY) ? "YES" : "NO";
        System.out.println(ans);
    }
}