#include <iostream>
using namespace std;

bool judge(double x1, double y1, double x2, double y2, double xp, double yp){
    double vecx = x2 - x1;
    double vecy = y2 - y1;
    double inner = vecx * xp + vecy * yp;
    if (inner > 0 ){
        return true;
    }else{
        return false;
    }
}

int main()
{
    double x1, x2, x3, xp, y1, y2 ,y3, yp;
    while (cin>>x1>>y1>>x2>>y2>>x3>>y3>>xp>>yp) {
        bool a, b, c;
        a = judge(x1, y1, x2, y2, xp, yp);
        b = judge(x1, y1, x3, y3, xp, yp);
        c = judge(x2, y2, x3, y3, xp, yp);
        if ((a == b) && (a == c) && (b == c)){
            cout << "YES" << endl;
        }else{
            cout << "NO" << endl;
        }
        
    }
 
    return 0;
}