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

typedef complex<double> P;

double cross(P a, P b){
	return (a.real() * b.imag() - a.imag() * b.real());
}

int main(void){
	double x,y;
	P p[4];

	while(1){
		for(int i=0;i<4;i++){
			if(!(cin>>x>>y)) return 0;
			p[i] = P(x,y);
		}
		if(cross(p[1]-p[0],p[3]-p[0]) > 0 &&
			 cross(p[2]-p[1],p[3]-p[1]) > 0 &&
			 cross(p[0]-p[2],p[3]-p[2]) > 0){
			cout<<"YES\n";
		}
		else{
			cout<<"NO\n";
		}
	}
}