#include <iostream>
using namespace std;

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