Loop counter in Workflow

Hello All,

I have a workflow with a loop. I want to count the iterations of the loop and report the number of times the loop ran.

I have a variable in my workflow to track the count. I can set an explicit value for my variable. But I am not able to set the value using a simple additions (e.g.  Count = Count + 1).

I've even tried assigning the current count to another variable and then adding 1 to the other variable without success.
e.g. 
Count2 = Count

Count = Count2 + 1

Is there a trick to doing simple math and assinging the result to a variable in a workflow?

Thanks,

-tomas