#include<iostream>
using namespace std;
int main(void){
    double x1,y1,x2,y2,x3,y3,x,y,a,b,c;
    while(cin >> x1 >> y1 >> x2 >> y2>> x3 >> y3 >> x >> y){
        a=((y-y2)*(x-x1)-(y-y1)*(x-x2))*((y3-y2)*(x3-x1)-(y3-y1)*(x3-x2));
        b=((y-y3)*(x-x2)-(y-y2)*(x-x3))*((y1-y3)*(x1-x2)-(y1-y2)*(x1-x3));
        c=((y-y3)*(x-x1)-(y-y1)*(x-x3))*((y2-y3)*(x2-x1)-(y2-y1)*(x2-x3));
        if(a>0 && b>0 && c>0)   cout << "YES" << endl;
        else                    cout << "NO" <<endl;
    }
}
