#include<stdio.h>
#include<iostream>
using namespace std;

double outer_product_z(double X[], double Y[]){
	return X[0]*Y[1]-X[1]*Y[0];
}
double x[4], y[4];
int main(){
	while(1){
		for(int i=0;i<4;i++){
			cin >> x[i] >> y[i];
		}
		double vec_ap[2] = {(x[3]-x[0]),(y[3]-y[0])};
		double vec_bp[2] = {(x[3]-x[1]),(y[3]-y[1])};
		double vec_cp[2] = {(x[3]-x[2]),(y[3]-y[2])};
		double vec_ab[2] = {(x[1]-x[0]),(y[1]-y[0])};
		double vec_bc[2] = {(x[2]-x[1]),(y[2]-y[1])};
		double vec_ca[2] = {(x[0]-x[2]),(y[0]-y[2])};

		if((outer_product_z(vec_ap,vec_ab)>0&&outer_product_z(vec_bp,vec_bc)>0&&outer_product_z(vec_cp,vec_ca)>0) || (outer_product_z(vec_ap,vec_ab)<0&&outer_product_z(vec_bp,vec_bc)<0&&outer_product_z(vec_cp,vec_ca)<0)) cout << "Yes" << endl;
		else cout << "No" << endl;

		if(cin.eof()) return 0;	
	}

}
