#include <iostream>
#include <cmath>
using namespace std;

int main(void){
ツ　ツ　double x1, y1, x2, y2, x3, y3, px, py;
ツ　ツ　double a, b, c, ap, bp, cp;
ツ　ツ　double tmp;
ツ　ツ　double s2, sa2, sb2, sc2;
ツ　ツ　double s, sa, sb, sc;

ツ　ツ　while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>px>>py){
ツ　ツ　ツ　ツ　a = sqrt(fabs((x2-x3) * (x2-x3) + (y2-y3) * (y2-y3)));
ツ　ツ　ツ　ツ　b = sqrt(fabs((x1-x3) * (x1-x3) + (y1-y3) * (y1-y3)));
ツ　ツ　ツ　ツ　c = sqrt(fabs((x1-x2) * (x1-x2) + (y1-y2) * (y1-y2)));
ツ　ツ　ツ　ツ　ap = sqrt(fabs((x1-px) * (x1-px) + (y1-py) * (y1-py)));
ツ　ツ　ツ　ツ　bp = sqrt(fabs((x2-px) * (x2-px) + (y2-py) * (y2-py)));
ツ　ツ　ツ　ツ　cp = sqrt(fabs((x3-px) * (x3-px) + (y3-py) * (y3-py)));
ツ　ツ　ツ　ツ　
ツ　ツ　ツ　ツ　tmp = (a+b+c) / 2;
ツ　ツ　ツ　ツ　s2 = tmp * (tmp-a) * (tmp-b) * (tmp-c);
ツ　ツ　ツ　ツ　s = sqrt(s2);
ツ　ツ　ツ　ツ　tmp = (a+bp+cp) / 2;
ツ　ツ　ツ　ツ　sa2 = tmp * (tmp-a) * (tmp-bp) * (tmp-cp);
ツ　ツ　ツ　ツ　sa = sqrt(sa2);
ツ　ツ　ツ　ツ　tmp = (b+ap+cp) / 2;
ツ　ツ　ツ　ツ　sb2 = tmp * (tmp-b) * (tmp-ap) * (tmp-cp);
ツ　ツ　ツ　ツ　sb = sqrt(sb2);
ツ　ツ　ツ　ツ　tmp = (c+ap+bp) / 2;
ツ　ツ　ツ　ツ　sc2 = tmp * (tmp-c) * (tmp-ap) * (tmp-bp);
ツ　ツ　ツ　ツ　sc = sqrt(sc2);
ツ　ツ　ツ　ツ　if(fabs(sa+sb+sc-s) < ie-9) cout << "YES" << endl;
ツ　ツ　ツ　ツ　else cout << "NO" << endl;
ツ　ツ　}
ツ　ツ　return 0;
}