Counting problem

I have a (large) spreadsheet with, amongst many other columns, the following sort of information:

ColB.....ColK.....Col L
Colour...Status...Live
-----------------------
R........Closed.....Y
A........Open.......Y
G........Closed
R........Open
G........Open

What I want is a formula that says:

count all occurrences of R/A/G in Col B but then subtract from that result the number of those that also have either 'Closed' in Col K or 'Y' in Col L. If both Col K and Col L are true then still only subtract 1.

In the above example, I would expect the results of the formula to be:

R ..... 1
A ..... 0
G ..... 1

Any help greatly appreciated, I'm getting tired now and it's getting late and my head is beginning to spin

That's absolutely fantastic - exactly what I wanted, worked a treat.

Many thanks - I can go to bed now