I need to count the number of cells in Column C that have a lesser or equal value to the adjacent cell in column D excluding cells that have a 0 value in both columns.

So the count for the following sequence would be 2
c1 = 23 and d1 = 24
C2 = 23 and D2 = 23
C3 = 0 and D3 = 0

I've tried using IF(AND and countif but I can't get the syntax right

The formula I came up with was =IF(AND(C:C="0",D:D="0","0",countif(C:C"<="D:D)) which doesn't work

Any help would be most welcome