#!/usr/bin/env python

import numpy as np

A = np.array([int(x) for x in input().split()])
B = np.array([int(x) for x in input().split()])
C = np.array([int(x) for x in input().split()])
D = np.array([int(x) for x in input().split()])

AB = B-A
AC = C-A
AD = D-A

Z = np.cross(AB, AC)
M = np.matrix([AB, AC, Z]).I

Co = AD * M

if Co[0, 0] <= 1 and Co[0, 1] <= 1:
    print('YES')
else:
    print('NO')