using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		int H = 120;
		int W = 120;
		int HW = H*W;
		List<int>[] E = new List<int>[HW];
		for(int i=0;i<HW;i++) E[i] = new List<int>();
		
		Func<int,int,int> enc = (r,c) => r*W+c;
		
		var deg = new Dictionary<int,int>();
		for(int i=0;i<N;i++){
			int v = enc(R0[i],C0[i]);
			int w = enc(R1[i],C1[i]);
			E[v].Add(w);
			E[w].Add(v);
			if(!deg.ContainsKey(v))deg.Add(v,0);deg[v]++;
			if(!deg.ContainsKey(w))deg.Add(w,0);deg[w]++;
		}
		
		bool[] used = new bool[HW];
		foreach(var v in deg.Keys){
			if(used[v]) continue;
			int nc = 0;
			int ne = 0;
			Queue<int> Q = new Queue<int>();
			used[v] = true;
			Q.Enqueue(v);
			while(Q.Count>0){
				var now = Q.Dequeue();
				nc++;
				ne += E[now].Count;
				foreach(var nxt in E[now]){
					if(!used[nxt]){
						used[nxt] = true;
						Q.Enqueue(nxt);
					}
				}
			}
			ne /= 2;
			if(nc >= ne) continue;
			Console.WriteLine("NO");
			return;
		}
		Console.WriteLine("YES");
		
		
	}
	int N;
	int[] R0,C0,R1,C1;
	public Sol(){
		N = ri();
		R0 = new int[N];
		R1 = new int[N];
		C0 = new int[N];
		C1 = new int[N];
		for(int i=0;i<N;i++){
			var d = ria();
			R0[i] = d[0];
			C0[i] = d[1];
			R1[i] = d[2];
			C1[i] = d[3];
			
		}
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}