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 lire=new Scanner(System.in);
      int n=lire.nextInt(); int x[]=new int[n];
      int y[]=new int[n];
        for (int i = 0; i < n; i++) {
          x[i]=lire.nextInt();
          y[i]=lire.nextInt();
         
        }
        if(find(x) || find(y))System.out.println("YES");
        else System.out.println("NO");
    }
    static boolean find(int x[]){
        int a=x[0];
        
            for (int i = 0; i < x.length; i++) {
                if(x[i]!=a)return false;
                
            }
            
        return true;
    }
}