#include <bits/stdc++.h>
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

#define forn(i,n) for (int i = 0; i < int(n); ++i)
#define FOR(i,x,y) for(long long i = (x) ; i <= (y) ; ++i)
typedef long long ll;
typedef long double ld;

int main() {  
  int n;
  cin >> n;
  
  vector<int> xs;
  vector<int> ys;

  forn(i,n) {
    int x, y;
    cin >> x >> y;
    xs.push_back(x);
    ys.push_back(y);
  }
  
  bool xs_res = true;
  forn(i,n-1) {
    if(xs[i] != xs[i+1]) {
      xs_res = false;
    }
  }
  bool ys_res = true;
  forn(i,n-1) {
    if(ys[i] != ys[i+1]) {
      ys_res = false;
    }
  }
  
  bool res = xs_res || ys_res;
  cout << (res?"YES":"NO") << endl;
}