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 x1= in.nextInt(),y1= in.nextInt();
        boolean v=true,h=true;
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            v= v&&(x==x1);
            h= h&&(y==y1);
        }
        System.out.println((v||h)?"YES":"NO");
    }
}