#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
template<typename T> using VT = vector<T>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back
template<typename T> inline bool chmax(T &a, T b){if (a < b){a = b;return true;}return false;}
template<typename T> inline bool chmin(T &a, T b){if (a > b){a = b;return true;}return false;}

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

const int SIZE = 120;
int N;
VVI graph(SIZE * SIZE);
bool dame = false;
bool used[SIZE * SIZE];

PII ip(int n) {
    return MP(n / SIZE, n % SIZE);
}
int pi(PII p) {
    return p.first * SIZE + p.second;
}
int pi(int r, int c) {
    return pi(MP(r, c));
}

int cnt = 0;
void dfs(int st, int now, int prev = -1) {
    cnt += used[now];
    if (cnt >= 2) {
        dame = true;
        return;
    }
    if (used[now]) return;
    used[now] = true;
    FORE(e, graph[now]) if (e != prev) {
        dfs(st, e, now);
    }
}

int main(void) {
    memset(used, false, sizeof(used));
    scanf("%d", &N);
    REP(i, N) {
        int a, b, c, d;
        scanf("%d%d%d%d", &a, &b, &c, &d);
        a--;b--;c--;d--;
        //cout<<a<<b<<c<<d<<endl;
        graph[pi(a, b)].EB(pi(c, d));
        graph[pi(c, d)].EB(pi(a, b));
    }
    REP(i, SIZE * SIZE) {
        cnt = 0;
        if (!used[i]) dfs(i, i);
        if (dame || cnt >= 2) {
            cout << "NO" << endl;
            return 0;
        }
    }
    cout << "YES" << endl;
}