#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
int main()
{ll n,n1;
	cin>>n;
	n1=n;
	ll x,y,countx=1,county=1;
	cin>>x>>y;
	--n;
	while(n--)
	{
		ll x2,y2;
		cin>>x2>>y2;
		if(x==x2)
		{
			countx++;
			}
else
if(y==y2)
{
	county++;
	}		
	}
	if(countx==n1 || county==n1)
{
	cout<<"YES";
	}
	else
	{
		cout<<"NO";
		}
	}