#include<iostream>
#include<string>
#include<algorithm>
#include<cmath>
using namespace std;
int main()
{
	int n;
	cin>>n;
	int x[n];
	int y[n];
	for(int i=0;i<n;i++)
	{
		cin>>x[i];
		cin>>y[i];
	}
	
	
	int count1=0,count2=0;
    
	
	
	for(int i=1;i<n;i++)
	{
		
		if(x[i]==x[i-1])
		count1++;
		else
		{
			count1=0;
			break;
		}
	
	}
	for(int i=1;i<n;i++)
	{
		
		if(y[i]==y[i-1])
		count2++;
			else
		{
			count2=0;
			break;
		}
	}
	//cout<<count1<<" "<<count2;
	if(count1==0&&count2==0)
	cout<<"NO";
	else
	cout<<"YES";
	
	
	
}