#include <iostream>
#include <cmath>

using namespace std;

inline double sq (double x) {
    return x * x;
}

double rad (double x1, double y1, double x2, double y2) {
    return acos((x1 * x2 + y1 + y2) /
        (sqrt(sq(x1) + sq(y1)) * sqrt(sq(x2) + sq(y2))));
}

int main (void) {
    double x1, x2, x3, xp;
    double y1, y2, y3, yp;
    for (;;) {
        cin >> x1; cin >> y1;
        cin >> x2; cin >> y2;
        cin >> x3; cin >> y3;
        cin >> xp; cin >> yp;
        if (cin.eof()) break;
        double d1, d2, d3;
        d1 = rad(x1 - xp, y1 - yp, x2 - xp, y2 - yp);
        d2 = rad(x1 - xp, y1 - yp, x3 - xp, y3 - yp);
        d3 = rad(x2 - xp, y2 - yp, x3 - xp, y3 - yp);
        if (d1 + d2 + d3 < 2 * M_PI)
            cout << "NO" << endl;
        else
            cout << "YES" << endl;
    }
    return 0;
}