#include <stdio.h>

int main()
{
 double xa, ya, xb, yb, xc, yc, xd, yd;
 scanf ("%lf%lf", &xa, &ya);
 scanf ("%lf%lf", &xb, &yb);
 scanf ("%lf%lf", &xc, &yc);
 scanf ("%lf%lf", &xd, &yd);
 printf (
 (((xd - xa)*(yb-ya)-(yd-ya)*(xb-xa))*((xc - xa)*(yb-ya)-(yc-ya)*(xb-xa)) >= 0) &&
 (((xd - xb)*(yc-yb)-(yd-yb)*(xc-xb))*((xa - xb)*(yc-yb)-(ya-yb)*(xc-xb)) >= 0) &&
 (((xd - xc)*(ya-yc)-(yd-yc)*(xa-xc))*((xb - xc)*(ya-yc)-(yb-yc)*(xa-xc)) >= 0 )?
 "yes": "no");
 return 0;
}