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 x1,y1,y2,x2=0;
        y2=0;
        x1=0;
        y1=0;
        if(n==2)
                {
                System.out.println("YES");
            }
        else
{
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            
           if(x==x1&&a0>0)
               {
               x2+=1;
           }
           if(y==y1&&a0>0)
               {
               y2+=1;
           }
            x1=x;
            y1=y;
           
        }
            if(x2==n-1||y2==n-1)
                {
                System.out.println("YES");
            }
            else{
                System.out.println("NO");
            }
        }
    }
}