#include <bits/stdc++.h>
using namespace std;

typedef long long LL;

#define PII       pair<int,int>
#define all(c)    c.begin(),c.end()
#define sz(c)     (int)c.size()
#define clr(c)    c.clear()
#define pb        push_back
#define mp        make_pair
#define cin(x)    scanf("%d",&x)
#define MOD		1000000007
#define EPS		1E-10

set<int> x,y;

int main()
{
	int n;
	cin >> n;
	while(n--)
	{
		int xx,yy;
		cin >> xx >> yy;
		x.insert(xx);
		y.insert(yy);
	}
	if(sz(x)==1 or sz(y) == 1)
		printf("YES");
	else
		printf("NO");
	return 0;
}