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 x[]=new int[n];
        int y[]=new int[n];
        for(int a0 = 0; a0 < n; a0++)
        {
            x[a0]=in.nextInt();
            y[a0]=in.nextInt();
        }   
        int flagx=1;
        int flagy=1;
        for(int i=0;i<n-1;i++)
        {
            if(x[i]!=x[i+1])
              flagx=0;
             
            if(y[i]!=y[i+1])
                flagy=0;
                    
        }
        if(flagx==1 || flagy==1)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}