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();
        boolean flag1= true;
        boolean flag2 = true;
        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();
        }
        
        for(int i = 0; i < n - 1; i++)
        {
            if(x[i] != x[i + 1]) flag1 = false;
        }     
        
        for(int i = 0; i < n - 1; i++)
        {
            if(y[i] != y[i + 1]) flag2 = false;
        }   
        
        if((flag1 && !flag2) || (!flag1 && flag2)) System.out.print("YES");
        else System.out.print("NO");
    }
}