#include <iostream>
using namespace std;

int main() {
  double x1, y1, x2, y2, x3, y3, xp, yp;
  while (cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> xp >> yp) {
    if (((x2 - x1) * (yp - y2) - (y2 - y1) * (xp - x2) > 0 &&
         (x3 - x2) * (yp - y3) - (y3 - y2) * (xp - x3) > 0 &&
         (x1 - x3) * (yp - y1) - (y1 - y3) * (xp - x1) > 0) ||
        ((x2 - x1) * (yp - y2) - (y2 - y1) * (xp - x2) < 0 &&
         (x3 - x2) * (yp - y3) - (y3 - y2) * (xp - x3) < 0 &&
         (x1 - x3) * (yp - y1) - (y1 - y3) * (xp - x1) < 0))
      cout << "YES\n";
    else
      cout << "NO\n";
  }

  return 0;
}

