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

//0 1->codeforces
#define LL "%lld"
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define PN printf("\n")
#define MODV 1000000007

typedef long long ll;
typedef double dbl;
typedef vector<int> vi;
typedef pair<int, int> pi;
void addmod(int &a, ll b){a=(a+b); if(a>=MODV)a-=MODV;}
void mulmod(int &a, ll b){a=(a*b)%MODV;}
int gi(){int a;scanf("%d",&a);return a;}
ll gll(){ll a;scanf(LL,&a);return a;}

int main() {
  int n=gi(), fx, fy;
  bool okx=true, oky=true;

  for(int i=0;i<n;i++){
    int tx=gi(), ty=gi();
    if(i){
      if(tx!=fx)okx=false;
      if(ty!=fy)oky=false;
    }
    else{
      fx=tx, fy=ty;
    }
  }
  if(okx || oky)cout<<"YES"<<endl;
  else cout<<"NO"<<endl;
  return 0;
}