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 i=0,j=0;
        int []x=new int[10];
        int []y=new int[10];
        for(int a0 = 0; a0 < n; a0++){
             x[a0] = in.nextInt();
             y[a0] = in.nextInt();
        }
        while(i<n){
            if(x[i]==x[i+1]){
                i++;    
            }
            else
                break;
        }
       
        while(j<n){
            if(y[j]==y[j+1]){
                j++;
            }
            else
                break;
        }
         if(i==n || j==n)
            System.out.print("YES");
        else
            System.out.print("NO");
    }
}