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

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define UB upper_bound
#define LB lower_bound
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

int n, a[100], r1[100], c1[100], r2[100], c2[100];
vector<pair<int, int>> vec[100][100];
int cy, vis[100][100];

void dfs(int x, int y, int v) {
	// cout << x << ", " << y << " " << v << endl;
	if(vis[x][y] == v - 2) { return; }
	if(vis[x][y] != 0) { cy++; return; }
	
	vis[x][y] = v;
	inc(i, vec[x][y].size()) {
		dfs(vec[x][y][i].FI, vec[x][y][i].SE, v + 1);
	}
	
	return;
}

int main() {
	cin >> n;
	inc(i, n) {
		cin >> r1[i] >> c1[i] >> r2[i] >> c2[i];
		r1[i]--; c1[i]--; r2[i]--; c2[i]--;
		
		vec[ r1[i] ][ c1[i] ].EB(r2[i], c2[i]);
		vec[ r2[i] ][ c2[i] ].EB(r1[i], c1[i]);
	}
	
	bool ans = true;
	inc(i, n) {
		if(vis[ r1[i] ][ c1[i] ] == 0) {
			cy = 0;
			dfs(r1[i], c1[i], 3);
			if(cy >= 2) { ans = false; break; }
		}
	}
	
	cout << (ans ? "YES" : "NO") << endl;
	
	return 0;
}