#include <iostream>
#include <iomanip>
#include <math.h>
#include <utility>
#include <cstdlib>
using namespace std;

int main(){
	double x[3],y[3],xp,yp;
	while(cin >> x[0] >> y[0] >> x[1] >> y[1] >> x[2] >> y[2] >> xp >> yp){
		bool ans=true;
		//???????????¨????????????
		double gaiseki;	//gaiseki[i]???????????????P0P1??¨????????????P0Q????????????z??§?¨?
		for(int i=0;i<3;i++){
			int k = (i+1)%3;
			double vx,vy,vpx,vpy;
			vx = x[k]-x[i];
			vy = y[k]-y[i];
			vpx = xp-x[i];
			vpy = yp-y[i];
			gaiseki = vx*vpy-vy*vpx;
			if(gaiseki<=0) ans = false;
		}
		if(ans){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		}
	}
	return 0;
}