#include<bits/stdc++.h>

#define MOD 1000000007
#define MAX 100005
#define ll long long
#define slld(t) scanf("%lld",&t)
#define sd(t) scanf("%d",&t)
#define pd(t) printf("%d\n",t)
#define plld(t) printf("%lld\n",t)
#define pcc pair<char,char>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define tr(container,it) for(typeof(container.begin()) it=container.begin();it!=container.end();it++)
#define mp(a,b) make_pair(a,b)
#define FF first
#define SS second
#define pb(x) push_back(x)
#define vi vector<int>
#define vpii vector<pii >
#define vll vector<ll>
#define clr(x) memset(x,0,sizeof(x))

using namespace std;

int main(){
	int n;
	sd(n);
	
	int x[15],y[15];
	
	for(int i=1;i<=n;i++){
		sd(x[i]);sd(y[i]);
	}
	
	bool h=1,v=1;
	
	for(int i=2;i<=n;i++){
		if(x[i]!=x[i-1]) h=0;
		if(y[i]!=y[i-1]) v=0;
	}
	
	if(h||v) printf("YES\n");
	else printf("NO\n");
}