#include <iostream>
using namespace std;

class Vector2{
public:
	Vector2(){}
	Vector2( double aX, double aY ) : x( aX ), y( aY ){}

	double dot( Vector2& a ){
		return ( x * a.x ) + ( y * a.y );
	}

	double x;
	double y;
};


int main(){
	Vector2 p0, p1, p2, q;

	cin >> p0.x >> p0.y >> p1.x >> p1.y >> p2.x >> p2.y >> q.x >> q.y;
	bool isInner = false;
	Vector2 a( p1.x - p0.x, p1.y - p0.y );
	Vector2 b( p2.x - p0.x, p2.y - p0.y );
	Vector2 c( q.x - p0.x, q.y - p0.y );

	double aa = a.dot( a );
	double ab = a.dot( b );
	double ac = a.dot( c );
	double bb = b.dot( b );
	double bc = b.dot( c );

	double s = ( bc*ab - ac*bb ) / ( ab*ab - aa*bb );
	if ( ( s > 0.0 ) && ( s < 1.0 ) ){
		double t = ( ac*ab - bc*aa ) / ( ab*ab - aa*bb );
		if ( ( t > 0.0 ) && ( s + t < 1.0 ) ){
			isInner = true;
		}
	}

	cout << ( isInner ? "Yes" : "No" ) << endl;

	return 0;
}