#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;
int main()
{
	int n,last,flag=0;
	int x[10],y[10];
	cin>>n;
	for(int i=0;i<n;i++)
	{
		//cout<<"da";
		cin>>x[i]>>y[i];
	}
	int flag1=0,flag2=0;
	for(int i=0;i<n-1;i++)
	{
		//cout<<"fff";
		float x1,x2,y1,y2;
		float m;
		
		x1 = x[i];
		x2 = x[i+1];
		y1 = y[i];
		y2 = y[i+1];
		if(i==0)
		{
			if(x1-x2==0)
			{
				flag1=1;
			}
			if(y1-y2==0)
			{
				flag2=1;
			}
		}
		else
		{
			if(flag1)
			{
				if(x1-x2!=0)
				{
					flag=1;
					break;
				}
			}
			if(flag2)
			{
				if(y1-y2!=0)
				{
					flag=1;
					break;
				}
			}
		}
	}

	if(flag==1)
		cout<<"NO"<<endl;
	else
		cout<<"YES"<<endl;
	return 0;
}