#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define per(i,a,b) for(ll i=(b-1);i>=(a);--i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

vector<int> uf, usz;
int nc;

void init(int n) {
  vector<int> uf_(n);
  vector<int> usz_(n, 1);
  uf = uf_;
  usz = usz_;
  nc = n;

  for (int i = 0; i < uf.size(); i++) {
    uf[i] = i;
  }
}

int find(int a) {
  return (uf[a] == a) ? a : uf[a] = find(uf[a]);
}

void union_(int a, int b) {
  a = find(a);
  b = find(b);

  if (a != b) {
    if (usz[a] >= usz[b]) {
      swap(a, b);
    }
    uf[a] = b;
    usz[b] += usz[a];
    nc--;
  }
}

int check(int a, int b) {
  return (find(a) == find(b)) ? 1 : 0;
}

int get_size(int a) {
  return usz[find(a)];
}

int main() {
  ll n;
  cin >> n;
  init(n);
  vector<pair<pair<ll, ll>, pair<ll, ll> > > v;
  rep(i, 0, n) {
    ll a, b, c, d;
    cin >> a >> b >> c >> d;
    v.pb(mp(mp(a, b), mp(c, d)));
  }
  rep(i, 0, v.sz) {
    rep(j, i + 1,v.sz) {
      if (v[i].fi.fi == v[j].fi.fi && v[i].fi.se == v[j].fi.se) {
        union_(i, j);
      }
      if (v[i].fi.fi == v[j].se.fi && v[i].fi.se == v[j].se.se) {
        union_(i, j);
      }
      if (v[i].se.fi == v[j].fi.fi && v[i].se.se == v[j].fi.se) {
        union_(i, j);
      }
      if (v[i].se.fi == v[j].se.fi && v[i].se.se == v[j].se.se) {
        union_(i, j);
      }
    }
  }
  set<ll> se;
  rep(i,0,n){
    se.insert(find(i));
  }
  vector<ll> vse(all(se));
  rep(i,0,vse.sz){
    vector<ll> v1;
    rep(j,0,v.sz){
      if(vse[i]==find(j)){
        v1.pb(j);
      }
    }
    set<pair<ll,ll> > se1;
    rep(j,0,v1.sz){
      se1.insert(mp(v[v1[j]].fi.fi,v[v1[j]].fi.se));
      se1.insert(mp(v[v1[j]].se.fi,v[v1[j]].se.se));
    }
    if(v1.sz>se1.sz){
      cout << "NO" << endl;
      return 0;
    }
  }
  cout << "YES" << endl;
  return 0;
}