CountA - stop counting in column when number changes positive or negative

Hello..... I can't figure this out. I have some columns of numbers which vary between positive and negative. Starting at the top of each column, I want to count down the number of cells (that are either positive or negative) and when the value in a cell changes sign, I want the count to stop and return how many cells the count got up to before being stopped. Hopefully this expalins... http://my.jetscreenshot.com/16785/20160425-zwrv-92kb
Many thanks

I probably should have posted this in the Formulas and Functions forum.......