I've a list of numbers, I need to summarize the first 4 greater than zero
cronologically eventhough they were in different places, and it could happen
only three or less were in the whole list.
Ex.
2 0 0 0 8 -3 -5 0 4 0 0 0 3 0 0 0 0 7 8 9 4 5 1 2 -8 -7

Sum. 2 + 8 + 4 + 3 = 17

easy hu? Thanks