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=in.nextInt();
        int q=in.nextInt();
        int x1=-1;
        int y1=-1;
        for(int a0 = 0; a0 < n-1; a0++){
            int  x = in.nextInt();
           int y= in.nextInt();
                if(p!=x){
                  x1=0;
                    
                }
            if(q!=y){
            y1=0;
               
            }
        }
        if(x1==-1||y1==-1){
            System.out.println("YES");
        }
        else
            System.out.println("NO");
    }
}