import sys

def highest_power_of_three(num_array):
	if num_array.len < 3:
		raise ValueError
	highest = highest_product_of_3 = highest_product_of_2 = 
		lowest_product_of_2 = lowest = num_array[0]
		
	for num in num_array[1:]:
		if num > highest:
			pass
		elif num < highest:
			pass
		else:
			pass