#include<iostream>
using namespace std;

int main()
{
	int n;
	cin >> n;
	int x[n],y[n];
	for(int i=0;i<n;i++)
		cin >> x[i] >> y[i];
	bool flag_x = true, flag_y = true;
	for(int i=1;i<n;i++)
	{
		if(x[i] != x[i-1])
			flag_x = false;
		if(y[i] != y[i-1])
			flag_y = false;
	}	
	if(flag_x || flag_y)
		cout << "YES";
	else
		cout << "NO";
}