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 arr[][]=new int[2][n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            arr[0][a0]=x;
            arr[1][a0]=y;
        }
        
        int count=0;
        for(int i=0;i<n-1;i++)
            {
            if(arr[0][i]==arr[0][i+1])
                {
                count++;
            }
        }

       int count1=0;
        for(int i=0;i<n-1;i++)
            {
            if(arr[1][i]==arr[1][i+1])
                {
                count1++;
            }
        }

        
        if(count==n-1 ||count1==n-1)
            {
            System.out.println("YES");
        }
        else
            {
            System.out.println("NO");
        }
        
        
        
        
    }
}