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 temp1=0,temp2=0,count1=0,count2=0,a0;
        for( a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(a0==0)
                {
                temp1=x;temp2=y;
            }
            else
                {
                if(temp1==x)
                    count1++;
                if(temp2==y)
                    count2++;
            }
        }
    
                   if(count1!=n-1&&count2!=n-1)
                   System.out.println("NO");
                   else
                   System.out.println("YES");
}
}