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 f1=0;
        int f2=0;
        for(int a0 = 1; a0 < n; a0++){
            if(x[a0]!=x[a0-1])
                f1=1;
            if(y[a0]!=y[a0-1])
                f2=1;

        
        }
        if(f1==0|| f2==0)
            System.out.println("YES");   
        else
             System.out.println("NO");
    }
}