# include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ULL = unsigned long long;
const double PI = acos(-1);
template<class T>constexpr T INF() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T HINF() { return INF<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); };
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); };
typedef pair<LL, LL> pii;
const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 };
const int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); };
LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; };
# define ALL(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        sort(ALL((wpwpw)));(wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(ALL((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(ALL((rprpr)),(rprpr).begin(),TU<char>)
# define FOR(i,tptpt,ypypy)   for(LL i=(tptpt);i<(ypypy);i++)
# define REP(i,upupu)         FOR(i,0,upupu)
# define INIT                 std::ios::sync_with_stdio(false);std::cin.tie(0)

struct UnionFind {
	UnionFind(size_t size) : v(size, -1) {}
	vector<int> v;

int root(int x) {
    return (v[x] < 0 ? x : v[x] = root(v[x]));
}

bool is_root(int x) {
    return x == root(x);
}

bool same(int x, int y) {
    return root(x) == root(y);
}

void unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x != y) {
		if (v[x] > v[y]) swap(x, y);
		v[x] += v[y];
		v[y] = x;
    }
}

int size(int x) {
    	return -v[root(x)];
	}
};

int n;
vector<int> g[10101];
bool vis[10101];
int u[10101], v[10101];
int cnt[10101];
int main(){
    INIT;
    cin >> n;
    UnionFind g(10101), uf(10101);
    REP(i, n){
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        u[i] = a*n + b, v[i] = c*n + d;
        g.unite(u[i], v[i]);
    }
    REP(i, n){
        if(uf.same(u[i], v[i])){
            cnt[g.root(u[i])]++;
        }else{
            uf.unite(u[i], v[i]);
        }
    }
    REP(i, 10101){
        if(cnt[i] >= 2){
            cout << "NO" << endl;
            return 0;
        }
    }
    cout << "YES" << endl;
}