#include <stdio.h>
using namespace std;
int main(){
double px,py;
double tx[3],ty[3];
bool flag;
bool v[3];
while(scanf("%lf %lf %lf %lf %lf %lf %lf %lf",&tx[0],&ty[0],&tx[1],&ty[1],&tx[2],&ty[2],&px,&py) == 8){
for(int i=0;i<3;i++){
tx[i]=tx[i]-px;
ty[i]=ty[i]-py;
}
for(int i=0;i<3;i++){
if((tx[i%3]*ty[(i+1)%3])-(ty[i%3]*tx[(i+1)%3])<0){
v[i]=true;
}else{
v[i]=false;
}
}
if(v[0]!=v[1]){
cout<<"NO"<<endl;
}else if(v[1]!=v[2]){
cout<<"NO"<<endl;
}else {
cout<<"YES"<<endl;
}
}
return 0;
}