//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 100010001;
const ll LINF = (ll)INF*INF*10;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}

const int N = 10000;

//head

inline int num(int i, int j) {return i*100 + j;}

int n;
vi G[N];
bitset<N> bits;
bool able = true;

inline void add(int i, int j) {
  G[i].emplace_back(j);
  G[j].emplace_back(i);
}

bool dfs(int i, int j) {
  //cout << i << ' ' << j << endl;
  for(int &ne:G[i]) if(ne != j and ne != -1) {
    if(bits.test(ne)) return false;
    bits.set(ne);
    if(!dfs(ne, i)) {
      if(bits.test(i)) return false;
      bits.flip(ne);
      bits.set(i);
      auto itr = find(all(G[ne]), i);
      ne = -1;
      *itr = -1;
    }
  }
  return true;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  rep(i, n) {
    int r0, c0, r1, c1;
    cin >> r0 >> c0 >> r1 >> c1;
    add(num(r0-1, c0-1), num(r1-1, c1-1));
  }

  rep(i, N) {
    if(!bits.test(i)) {
      if(!dfs(i, -1)) {
        able = false;
        break;
      }
    }
  }

  cout << (able?"YES":"NO") << endl;
}