def even_fibonacci_numbers(limit = 4000000):
	"""
	Returns the sum of the even-valued terms in the Fibonacci sequence,
	whose values do not exceed four million.
	"""
	n1, n2 = 1, 2
	even_sum = 0
	while (n2 <= limit):
		if n2%2 == 0:
			even_sum += n2
		temp = n2 + n1
		n1 = n2
		n2 = temp
	return even_sum