#include <bits/stdc++.h>
using namespace std;
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define mp(a,b) make_pair((a),(b))
#define pb(a) push_back((a))
#define all(x) (x).begin(),(x).end()
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#define fi first
#define se second
#define dbg(x) cout<<#x" = "<<((x))<<endl
template<class T,class U> ostream& operator<<(ostream& o, const pair<T,U> &p){o<<"("<<p.fi<<","<<p.se<<")";return o;}
template<class T> ostream& operator<<(ostream& o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}

#define INF 2147483600
#define long long long

typedef pair<int, int> P;

class UnionFind {
public:
  vector<int> par, rank; // parent(negative := its root and abs-value is its size), depth
  UnionFind(int sz) : par(sz, -1), rank(sz, 0){}
  int find(int x){
    if(par[x]<0) return x;
    else return par[x] = find(par[x]);
  }
  void unite(int x, int y){
    x=find(x); y=find(y);
    if(x==y) return;  // already belong to same tree
    if(rank[x] < rank[y]){  // y becomes parent node
      par[y] += par[x];
      par[x] = y;
    } else {  // x becomes parent node
      par[x] += par[y];
      par[y] = x;
      if(rank[x]==rank[y]) rank[x]++;
    }
  }
  bool same(int x, int y){ return find(x) == find(y); }
  int size(int x){ return -par[find(x)]; }
}; // END class UnionFind

vector<int> tbl[100][100];

int main(){
  int n;
  cin>>n;
  vector<pair<P,P>> vec(n);
  UnionFind edge(100*100);
  UnionFind vtx(n);
  rep(i,n){
    int a,b,c,d;
    cin>>a>>b>>c>>d;
    a--;b--;c--;d--;
    vec[i] = mp(mp(a,b),mp(c,d));
    tbl[a][b].pb(i);
    tbl[c][d].pb(i);
    edge.unite(a*100+b, c*100+d);
  }
  rep(i,n){
    for(auto v : tbl[vec[i].fi.fi][vec[i].fi.se]) vtx.unite(i,v);
    for(auto v : tbl[vec[i].se.fi][vec[i].se.se]) vtx.unite(i,v);
  }
  rep(i,n) if(vtx.par[i]<0){ // おや
    int a = vec[i].fi.fi, b = vec[i].fi.se;
    if(vtx.size(i) > edge.size(a*100+b)){
      cout<<"NO"<<endl;
      return 0;
    }
  }
  cout<<"YES"<<endl;
  return 0;
}