#include <stdio.h>
#include <stdlib.h>
#include<iostream>
#include<math.h>
#include<vector>
using namespace std;

float area(float x1, float y1, float x2, float y2, float x3, float y3)
{
    return fabs((x1*(y2-y3) + x2*(y3-y1)+ x3*(y1-y2))/2.0);
}


bool isInside(float x1, float y1, float x2, float y2, float x3, float y3, float x, float y)
{
    /* Calculate area of triangle ABC */
    float A = area (x1, y1, x2, y2, x3, y3);
    //cout<<A<<endl;
    /* Calculate area of triangle PBC */
    float A1 = area (x, y, x2, y2, x3, y3);//cout<<A1<<endl;

    /* Calculate area of triangle PAC */
    float A2 = area (x, y, x1, y1, x3, y3);//cout<<A2<<endl;

    /* Calculate area of triangle PAB */
    float A3 = area (x,y,x1, y1, x2, y2);//cout<<A3<<endl;
    //cout<<A1+A2+A3<<endl;

    /* Check if sum of A1, A2 and A3 is same as A */
    return (A == A1 + A2 + A3);
}

/* Driver program to test above function */
int main()
{
    /* Let us check whether the point P(10, 15) lies inside the triangle
       formed by A(0, 0), B(20, 0) and C(10, 30) */
    float x1, y1, x2 , y2, x3, y3,xp,yp;
    while(scanf("%f %f %f %f %f %f %f %f",&x1,&y1,&x2,&y2,&x3,&y3,&xp,&yp)==8)
    {
        if (isInside(x1, y1, x2, y2, x3, y3,xp,yp))
            printf ("YES\n");
        else
            printf ("NO\n");
    }

    return 0;
}