import java.io.*;
import java.util.*;
import java.math.*;
import java.text.*;
public class Main
{ 
public static void main(String[] args)throws java.lang.Exception
{
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
PrintWriter out=new PrintWriter(System.out);

int i,n,x1,y1,x_cnt,y_cnt;


n=Integer.parseInt(in.readLine());

int[] x=new int[n];
int[] y=new int[n];

for(i=0;i<n;i++)
{
StringTokenizer st1=new StringTokenizer(in.readLine());

x[i]=Integer.valueOf(st1.nextToken());
y[i]=Integer.valueOf(st1.nextToken());
}


x1=x[0];
y1=y[0];
x_cnt=0;
y_cnt=0;

for(i=0;i<n;i++)
{
	if(x[i]==x1)
	{
		x_cnt++;
	}

	if(y[i]==y1)
	{
		y_cnt++;
	}
}


if(x_cnt==n || y_cnt==n)
{
	out.println("YES");
}
else
{
	out.println("NO");
}




out.flush();
out.close();
}
}