#include<set>
#include<map>
#include<cmath>
#include<queue>
#include<stack>
#include<vector>
#include<cctype>
#include<cstdio>
#include<string>
#include<sstream>
#include<cstring>
#include<cstdlib>
#include<fstream>
#include<iterator>
#include<iostream>
#include<algorithm>

using namespace std;

#pragma comment(linker,"/STACK:16777216")
#pragma warning(disable:4786)

#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))
#define myabs(a) ((a)<0?(-(a)):(a))
#define pi acos(-1.0)
#define CLR(a) memset(a,0,sizeof(a))
#define SET(a) memset(a,-1,sizeof(a))
#define pb push_back
#define all(a) a.begin(),a.end()
#define ff first
#define ss second
#define eps 1e-9
#define root 1
#define lft 2*idx
#define rgt 2*idx+1
#define cllft lft,st,mid
#define clrgt rgt,mid+1,ed
#define inf (1<<29)
#define i64 long long
#define MX 1000002
#define MOD 1000000007

typedef pair<int,int> pii;

int main(){
	//freopen("in.txt","r",stdin);
	int x[15],y[15],n,i,flag=0,fx=0,fy=0;
	cin>>n;
	for(i=0;i<n;i++){
	    cin>>x[i]>>y[i];
	}
	for(i=1;i<n;i++)if(x[i]!=x[i-1])fx=1;
	for(i=1;i<n;i++)if(y[i]!=y[i-1])fy=1;

	if(fx && fy)cout<<"NO"<<endl;
	else cout<<"YES"<<endl;
	return 0;
}