#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int main(){
  double x1,x2,x3,y1,y2,y3,x,y;
  double a,b,c,s,ans;
  while(scanf("%lf %lf %lf %lf %lf %lf %lf %lf",&x1,&x2,&x3,&y1,&y2,&y3,&x,&y)!=EOF){
    a=x1*(y2-y3)+x2*(y3-y1)+x3*(y1-y2);
    b=x*(y-y1)+x1*(y1-y2)+x2*(y2-y);
    c=x*(y-y2)+x2*(y2-y3)+x3*(y3-y);
    s=x*(y-y3)+x3*(y3-y1)+x1*(y1-y);
    if(a<b && a<c && a<s || a>b && a>c && a>s){
      cout << "YES" << endl;
    }else{
      cout << "NO" << endl;
    }
  }
  return 0;
}