#include <iostream>
#include <complex>
using namespace std;
typedef complex<double> xy_t;
double cross_product(xy_t a, xy_t b) { return (conj(a)*b).imag(); }
const double eps = 1e-11;
double x[4],y[4];
int main() {
    while(true){
        for(int i=0; i<4; ++i){
            cin >> x[i] >> y[i];}
            if(!cin) break;
            xy_t a(x[0],y[0]),b(x[1],y[1]),c(x[2],y[2]),p(x[3],y[3]);
            double pab = cross_product(a-p, b-p);
            double pbc = cross_product(b-p, c-p);
            double pca = cross_product(c-p, a-p);
            bool ok = abs(pab+pbc+pca) == abs(pab)+abs(pbc)+abs(pca);
            cout << (ok ? "YES" : "NO") << endl;
            }
    return 0;
}