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 = 0;
        int y = 0;
        
        int xLine = 0;
        int yLine = 0;
       
        
        boolean xLineFlag = true;
        boolean yLineFlag = false;
        
        for(int a0 = 0; a0 < n; a0++){
            x = in.nextInt();
            y = in.nextInt();
            
            if(a0 == 0){
                xLine = x;
                yLine = y;
            } else {
                
                if(xLine != x){
                    xLineFlag = false;
                }
                
                if(yLine != y) {
                    yLineFlag = false;
                }
            }
            
        }
        
        if(yLineFlag == true || xLineFlag == true){
            System.out.print("YES");
        } else {
            System.out.print("NO");
        }
            
        
    
        
    }
}