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

void couten(double x[], double y[], double &cx, double &cy){
	double a2, b2, c2, a, b, c, s, S2;
	a2 = abs((x[2]-x[1])*(x[2]-x[1]) + (y[2]-y[1])*(y[2]-y[1]));
    b2 = abs((x[0]-x[2])*(x[0]-x[2]) + (y[0]-y[2])*(y[0]-y[2]));
    c2 = abs((x[1]-x[0])*(x[1]-x[0]) + (y[1]-y[0])*(y[1]-y[0]));
    a = sqrt(a2); b = sqrt(b2); c = sqrt(c2);
	if((a + b + c) == 0){
		s = 0;
		cx = 0;
		cy = 0;
	} else{
		s = (a + b + c) / 2;S2 = s * (s-a) * (s-b) * (s-c);
		cx = (a2*(b2+c2-a2)*x[0] + b2*(c2+a2-b2)*x[1] + c2*(a2+b2-c2)*x[2]) / (16 * S2);
		cy = (a2*(b2+c2-a2)*y[0] + b2*(c2+a2-b2)*y[1] + c2*(a2+b2-c2)*y[2]) / (16 * S2);
	}
}

int hantei(double x[], double y[], double &cx, double &cy, double xp, double yp){
	bool flag[3];
	double tc, tp, tcc, tpp;
	x[3] = x[0]; y[3] = y[0];
	for(int i = 0; i < 3; i++){
		tc = (x[i] - x[i + 1]) * (cy - y[i]) + (y[i] - y[i + 1]) * (x[i] - cx);
		tp = (x[i] - x[i + 1]) * (yp - y[i]) + (y[i] - y[i + 1]) * (x[i] - xp);
		if(tc * tp >= 0){
			flag[i] = true;
		} else{
			continue;
		}
	}
	if(flag[0] == true && flag[1] == true && flag[2] == true){
		return 1;
	} else{
		return 0;
	}
}


int main(){
	double x[3], y[3], xp, yp, cxx, cyy;
	double &cx = cxx, &cy = cyy;
	
	while(cin >>x[0] >>y[0] >>x[1] >>y[1] >>x[2] >>y[2] >>xp >>yp){
		couten(x, y, cx, cy);
		if(hantei(x, y, cx, cy, xp, yp)){
			cout <<"Yes"<<endl;
		} else{
			cout <<"No"<<endl;
		}
	}
	
	return 0;
}
	