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

#define fi first
#define se second
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define each(itr,v) for(auto itr:v)
#define pb(s) push_back(s)
#define mp(a,b) make_pair(a,b)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define maxch(x,y) x=max(x,y)
#define minch(x,y) x=min(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt(x) bitset<32>(x).count()

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;
typedef pair<ll, ll> PL;
typedef pair<P, ll> PPL;

#define INF INT_MAX/3

#define MAX_V 12321

int V;
vector<int> G[MAX_V];
int match[MAX_V];
bool used[MAX_V];

void init(int v){
	V=v;
	for(int i=0;i<V;i++)G[i].clear();
}

void add_edge(int u,int v){
	G[u].push_back(v);
	G[v].push_back(u);
}

bool dfs(int v){
	used[v]=true;
	for(int i=0; i<G[v].size();i++){
		int u=G[v][i],w=match[u];
		if(w<0||(!used[w]&&dfs(w))){
			match[v]=u;
			match[u]=v;
			return true;
		}
	}
	return false;
}

int bipartite_match(){
	int res=0;
	memset(match,-1,sizeof(match));
	for(int v=0; v<V;v++){
		if(match[v]<0){
			memset(used,0,sizeof(used));
			if(dfs(v))res++;
		}
	}
	return res;
}

int n;

int main(){
	cin.sync_with_stdio(false);
	cin>>n;
	init(10100);
	rep(i,n){
		int r1,c1,r2,c2;
		cin>>r1>>c1>>r2>>c2;
		r1--; r2--; c1--; c2--;
		add_edge(i,r1*100+c1+n);
		add_edge(i,r2*100+c2+n);
	}
	if(bipartite_match()==n)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;
	return 0;
}