def get_digit_number(n, count):
	"""
	:param n: int, input a positive integer number
	:param count: int, input a initial number (usually 1) to count how many digits in a given number (n)
	:return: int, return a number that represents the number of digit in n
	"""
	if n < 10:
		return count
	else:
		n /= 10
		count += 1
		count = get_digit_number(n, count)
		return count