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);
        Set<Integer> set1 = new HashSet<>();
        Set<Integer> set2 = new HashSet<>();
        int n = in.nextInt();
        for(int a0 = 0; a0 < n; a0++){
            set1.add(in.nextInt());
            set2.add(in.nextInt());
        }
        System.out.println((set1.size()>1 & set2.size()>1 ) ? "NO" : "YES");
    }
}