#include <iostream>
#include <stdio.h>
#include <utility>
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;
}