import java.io.*;
import java.util.*;
import java.math.*;
class HemantOne
{
	public static void main(String []args)
	{
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		int i=0;
		boolean flg1=true,flg2=true;
		int arr1[]=new int[n];
		int arr2[]=new int[n];
		int x=n*2,j=0,k=0;
		for(i=0;i<x;i++)
		{
			if(i%2==0)
			{
				arr1[j]=sc.nextInt();
				j++;
			}
			else
			{
				arr2[k]=sc.nextInt();
				k++;
			}
		}
		for(i=0;i<n-1;i++)
		{
			if(arr1[i]!=arr1[i+1])
			{
				flg1=false;
			}
			if(arr2[i]!=arr2[i+1])
			{
				flg2=false;
			}
		}
		if(flg1==true||flg2==true)
			System.out.println("YES");
		else
			System.out.println("NO");
	}
}