#include<bits/stdc++.h>
using namespace std;
#define fast cin.sync_with_stdio(0);cin.tie(0)
#define pii pair<int,int>
#define ff first
#define ss second
#define mp make_pair
#define pb push_back
#define INF 99999999
#define N 100005
#define ll long long
#define llu unsigned long long 
#define MOD 1000000007
int x[N],y[N];
int main()
{
	int n,i,cnt1=0,cnt2=0;
	cin>>n;
	for(i=0;i<n;i++)
	  cin>>x[i]>>y[i];
	for(i=0;i<n-1;i++)
	{
		if(x[i]==x[i+1])
		  cnt1++;
	}
	for(i=0;i<n-1;i++)
	{
		if(y[i]==y[i+1])
		  cnt2++;
	}
	if(cnt1==n-1||cnt2==n-1)
	  cout<<"YES\n";
	 else
	  cout<<"NO\n";
	return 0;
}