#include<bits/stdc++.h>
#include<vector>
#include<list>
#include<stack>
#include<queue>
#include<algorithm>
using namespace std;

int main(){
    double x1,y1,x2,y2,x3,y3,xp,yp;
    while(scanf("%lf %lf %lf %lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&x3,&y3,&xp,&yp)!=EOF){
        if (((x2-x1)*(y2-y3))-((y1-y3)*(x2-x3))>0 && ((x3-x2)*(y3-yp))-((y1-yp)*(x3-xp))>0) {
        //if(((x2-x1)*(y2-yp)-(y2-y1)*(x2-xp)>0)&&((x3-x2)*(y3-yp)-(y3-y2)*(x3-xp)>0)&&((x1-x3)*(y1-yp)-(y1-y3)*(x1-xp)>0)){
            printf("YES\n");
        //}else if(((x2-x1)*(y2-yp)-(y2-y1)*(x2-xp)<0)&&((x3-x2)*(y3-yp)-(y3-y2)*(x3-xp)<0)&&((x1-x3)*(y1-yp)-(y1-y3)*(x1-xp)<0)){
        //    printf("YES\n");
        }else{
            printf("NO\n");
        }

    }
    return 0;
}