#include <iostream>
#include <complex>
using namespace std;

typedef complex<double> point;

double gaiseki(point a,point b){
	return (a*conj(b)).imag();
}

int main(void){
	double x,y;
	while(cin>>x>>y){
		point a(x,y);
		cin>>x>>y;
		point b(x,y);
		cin>>x>>y;
		point c(x,y);
		cin>>x>>y;
		point p(x,y);
		if(gaiseki(b-a,p-a)>=0.0||gaiseki(c-b,p-b)>=0.0||gaiseki(a-c,p-c)>=0.0){
			cout<<"NO"<<endl;
			continue;
		}
		cout<<"YES"<<endl;
	}
	return 0;
}