def sub_vector(x1, y1, x2, y2)
	return x1 - x2, y1 - y2
end

while line = gets do
	x1, y1, x2, y2, x3, y3, xp, yp = line.split.map(&:to_f)

	*ab = sub_vector(x2, y2, x1, y1)
	*bp = sub_vector(xp, yp, x2, y2)

	*bc = sub_vector(x3, y3, x2, y2)
	*cp = sub_vector(xp, yp, x3, y3)

	*ca = sub_vector(x1, y1, x3, y3)
	*ap = sub_vector(xp, yp, x1, y1)
	
	c1 = ab[0] * bp[1] - ab[1] * bp[0]
	c2 = bc[0] * cp[1] - bc[1] * cp[0]
	c3 = ca[0] * ap[1] - ca[1] * ap[0]
	
	if (c1 > 0 && c2 > 0 && c3 > 0) ||
	   (c1 < 0 && c2 < 0 && c3 < 0); then
	   puts "YES"
	else
	   puts "NO"
	end
end