# decimal to binary
class Stack:

	def __init__(self):
		self.items = []

	def isempty(self):
		return len(self.items) == 0

	def push(self, item):
		self.items.append(item)

	def pop(self):
		self.items.pop()

	def size(self):
		return len(self.items)


def divide_by2(dec):
	binStack = Stack()
	while dec > 0:
		rem = dec % 2
		binStack.push(rem)
		dec = dec / 2


	binString = ""
	while not binStack.isempty():
		binString = binString + str(binStack.pop())

	return binString

print "Result: " + divide_by2(42)