list1=[13,13,13,1,2,13,14,15,16,13,13,44,13,13,13]

for i,e in enumerate(list1):
	if i+1 == len(list1):
		break
	if list1[i] == 13 and list1[i+1] == 13:
		while list1[i]==list1[i+1] and list1[i+1]<=len(list1):
			list1.pop(i)

while 13 in list1:
	if list1[-1] == 13:
		list1.pop()
		print(list1)
	else:
		trzyn=list1.index(13)
		list1.pop(trzyn+1)
		list1.pop(trzyn)

print(sum(list1))