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) { int h = 0 ,v = 0;
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int a = in.nextInt();
        int b = in.nextInt();
        for(int a0 = 0; a0 < n-1; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(x == a)
                h = 1 ;
            else
                h = 0;
            if(y == b)
                v = 1 ;
            else
                v = 0 ;
            if(h == 0 && v == 0)
            {    System.out.println("NO");
            break ;
            }
                
        }
      if(h == 1 || v == 1)
          System.out.println("YES");
    }
}