different colors for a matrix

Hi.
I have a matrix containing 3 row groups and 2 column groups and of course a detail area.
I want to show the detail area in different colors according to the row number.For example
1. row -->blue
2. row -->green
3. row -->blue

4. row -->green
5. row -->blue

6. row -->green
and so this goes....

I used the =IIF(RunningValue(FieldName, CountDistinct, "matrix1") Mod 2 , color1, color2)
for the detail's backgroundColor property
But it didn't work as I want.This caused a result like this:
1. row -->blue

2. row -->blue

3. row -->blue

4. row -->green

5. row -->blue

6. row -->green
.......
And I didn't understand how it works.
How could I do this.Which group name should I use in the formula?
Or do you have another idea for this problem?

Hi,

Chris Hayes blog has all the details you need:

http://blogs.msdn.com/chrishays/

Regards,

Sanjay