#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 100000000

typedef long long ll;

double dot(pair<double,double> p, pair<double,double> q) {
    return p.first * q.first + p.second * q.second;
}

double det(pair<double,double> p, pair<double,double> q) {
    return p.first * q.second - p.second * q.first;
}

pair<double,double> operator +(pair<double,double> p, pair<double,double> q) {
    return make_pair(p.first+q.first,p.second+q.second);
}

pair<double,double> operator -(pair<double,double> p, pair<double,double> q) {
    return make_pair(p.first-q.first,p.second-q.second);
}

pair<double,double> operator *(double s, pair<double,double> p) {
    return make_pair(p.first*s,p.second*s);
}

int main() {
    int i, j, k, l, cnt;
    pair<double,double> p[5];
    rep (i,5) {
        double x, y;
        cin >> x >> y;
        p[i] = make_pair(x,y);
    }
    cnt = 0;
    rep (i,4) REP (j,i+1,5) {
        int cross = 0;
        rep (k,5) REP (l,k+1,5) {
            if (k != i && k != j && l != i && l != j && det(p[j]-p[i],p[l]-p[k]) != 0) {
                double t = det(p[l]-p[k],p[k]-p[i])/det(p[l]-p[k],p[j]-p[i]);
                auto q = p[i] + t*(p[j]-p[i]);
                if (dot(p[i]-q,p[j]-q) < 0 && dot(p[k]-q,p[l]-q) < 0)
                    cross++;
            }
        }
        if (cross != 0 && cross != 2) {
            cout << "NO" << endl;
            return 0;
        }
        if (cross == 2) cnt++;
    }
    if (cnt == 5)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}