sort_special

def sort_special(a):
	new_a = []
	while len(a) > 1:
		new_a.append(min(a))
		a.remove(min(a))
		new_a.append(max(a))
		a.remove(max(a))
	return new_a


a = [54,26,93,17,77,31,44,55,20]
print(sort_special(a))