counting number of occurences since last bad item

[brian_2me]

Hello,

I'm looking to get a formula which will count the number of entries based on criteria of number of good entries since last known bad entry. I have tried to explain this in the attached spreadsheet.

Column A→C = rawdata
Col A = Item
Col B = Good / Bad
Col C = Quantity

In column D i have added the expected result
D8 = 2 as opposed to a count of Col A = "Apples" and Col B result = "Good", a standard countif which would return 3 (Row 2,6 + 8) but as row 5 has Col B result as "Bad" i need to start the counter again to just include row 6 + 8