#include <bits/stdc++.h>

#define icin(x) scanf("%d",&x)
#define lcin(x) scanf("%lld",&x)
#define LL long long
#define F first
#define S second
#define pb push_back
#define N 512345
#define INF (1e9+1)
#define mod ((LL)(1e9+7))

using namespace std;



vector< vector<int> > gr;

int main()
{
	int n;
	icin(n);
	vector< int > x(n),y(n);
	for(int i=0;i<n;i++)
	{
		icin(x[i]);
		icin(y[i]);
	}
	bool f1=1,f2=1;
	int a=x[0],b=y[0];
	for(int i=0;i<n;i++)
	{
		if(x[i]!=a)
			f1=0;
		if(y[i]!=b)
			f2=0;
	}
	if( (f1|f2) == 0)
		printf("NO");
	else
		printf("YES");
}