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 xc=0,yc=0;
		int xp=-999,yp=-999;
		for (int a0 = 0; a0 < n; a0++)
		{
			int x = in.nextInt();
			int y = in.nextInt();
			if(x==xp)
				xc++;
			if(y==yp)
				yc++;
			xp=x;
			yp=y;
			
			
		}
		if(xc==n-1||yc==n-1)
			System.out.println("YES");
		else
			System.out.println("NO");
	}
}