#include <iostream>
using namespace std;

int main() {
  double x1, y1, x2, y2, x3, y3, xp, yp;
  double vx1, vy1, vx2, vy2, vxp, vyp;
  double s, t;
  while (cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> xp >> yp) {
    vx1 = x2-x1;
    vy1 = y2-y1;
    vx2 = x3-x1;
    vy2 = y3-y1;
    vxp = xp-x1;
    vyp = yp-y1;
    s = (vyp*vx2 - vxp*vy2) / (vy1*vx2-vx1*vy2);
    if (vx2) {
      t = (vxp-vx1*s) / vx2;
    } else {
      t = (vyp-vy1*s) / vy2;
    }

    if (s>0.0 && t>0.0 && s+t<1.0) {
      cout << "YES" << endl;
    } else {
      cout << "NO" << endl;
    }
  }
  return 0;
}