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 p,q;
         p = in.nextInt();
          q = in.nextInt();
       int cx=1,cy=1;
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(p==x)
                cx++;
            if(q==y)
                cy++;
        }
        
        System.out.println((cx==n || cy == n) ? "YES":"NO");
    }
}