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++){
            int x = in.nextInt();
            int y = in.nextInt();
             X[a0]=x;
            Y[a0]=y;
        }
                int first=X[0];
        int second=Y[0];
        int count=0;
        int ycount=0;
        for (int element : X) {
            if (element != first) {
            	for (int element2 : Y){
            		if (element != first) {
                         System.out.println("NO");
                         break;
                     }
            		 else{
            			 ycount++;
            			
            		 }
            		
            	}
            	
            
            }
            else {
            	count++;
            	
            }
        }
        
        if(count==n){
        	System.out.println("YES");
        }
        else if(ycount==n){
        	System.out.println("YES");
        }
        

    }
}