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();
        HashSet<Integer> x=new HashSet<Integer>();
        HashSet<Integer> y=new HashSet<Integer>();
        for(int i = 0; i < n; i++){
            x.add(new Integer(in.nextInt()));
            y.add(new Integer(in.nextInt()));
            
        }
        if(x.size()==1 || y.size()==1)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}