#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<vector<int> > matchY(n, vector<int>(2));
    vector<vector<int> > matchX(n, vector<int>(2));
    vector<vector<set<pair<int, int> > > > s(101, vector<set<pair<int, int> > >(101));
    for(int i=0; i<n; ++i){
        cin >> matchY[i][0] >> matchX[i][0] >> matchY[i][1] >> matchX[i][1];
        s[matchY[i][0]][matchX[i][0]].insert(make_pair(i, 0));
        s[matchY[i][1]][matchX[i][1]].insert(make_pair(i, 1));
    }

    queue<pair<int, int> > q;
    for(int y=1; y<=100; ++y){
        for(int x=1; x<=100; ++x){
            if(s[y][x].size() == 1)
                q.push(make_pair(y, x));
        }
    }

    while(!q.empty()){
        int y, x;
        tie(y, x) = q.front();
        q.pop();
        if(s[y][x].empty())
            continue;
            
        int i, j;
        tie(i, j) = *s[y][x].begin();
        s[y][x].erase(make_pair(i, j));

        int y2 = matchY[i][j^1];
        int x2 = matchX[i][j^1];
        s[y2][x2].erase(make_pair(i, j^1));
        if(s[y2][x2].size() == 1)
            q.push(make_pair(y2, x2));
    }

    for(int y=1; y<=100; ++y){
        for(int x=1; x<=100; ++x){
            if(s[y][x].size() > 2){
                cout << "NO" << endl;
                return 0;
            }
        }
    }

    cout << "YES" << endl;
    return 0;
}