import java.util.Scanner;

public class Solution {

	public static void main(String[] args) {
		Scanner in=new Scanner(System.in);
		int n=in.nextInt();
		int xt=in.nextInt();
		int yt=in.nextInt();
		int xc=1;
		int yc=1;
		for(int i=0; i<n-1; i++){
			int x=in.nextInt();
			int y=in.nextInt();
			if(x==xt)
				xc++;
			if(y==yt)
				yc++;
		}
		in.close();
		if(xc==n || yc==n)
			System.out.println("YES");
		else
			System.out.println("NO");
	}

}