#include <iostream>


bool checkSlope(double x1,double y1 ,double x2 ,double y2,double x3,double y3 ,double x,double y){
	double slope1 = (y2-y1)/(x2-x1);
	double slope2 = (y3-y1)/(x3-x1);
	double slopep = (y-y1)/(x-x1);

	if(slope1 > slope2){
					if(slope1 > slopep && slopep > slope2){
									return true;
					}else{
									return false;
					}
	}else{
					if(slope2 > slopep && slopep > slope1){
									return true;
					}else{
									return false;
					}
	}
}


int main(int argc, char *argv[])
{
	double x1,x2,x3,y1,y2,y3,x,y;

	while(std::cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x >> y){

	bool flag[3];

	flag[0] = checkSlope(x1,y1,x2,y2,x3,y3,x,y);
	flag[1] = checkSlope(x2,y2,x1,y1,x3,y3,x,y);
	flag[2] = checkSlope(x3,y3,x1,y1,x2,y2,x,y);

	bool fukumu;

	for(int i = 0; i < 3; i++){
					if(flag[i]=true){
									fukumu = true;
					}else{
									fukumu = false;
									break;
					}
	}

	if(fukumu=true){
					std::cout << "YES" << std::endl;
	}else{
					std::cout << "NO" << std::endl;
	}

}
}