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

double cross(complex<double> A, complex<double> B){
	return (conj(A)*B).imag();
}

int main(){
	complex<double> Points[3], P;
	while(true){
		double x, y;
		for(int i=0; i<3; i++){
			cin >> x >> y;
			Points[i] = {x, y};
		}
		cin >> x >> y;
		P = {x, y};

		if(!cin)break;

		int sum = 0;
		for(int i=0; i<3; i++){
			sum += cross((Points[(i+1)%3]-Points[i]), (P-Points[i])) > 0;
		}
		cout << (sum==0 || sum==3? "Yes":"No") << endl;
	}
	return 0;
}
