How to generate an identity column in hyperion interactive reporting?

I want to display an auto-incremented series (basically the row number) in a new column. How do I go about doing this in Hyperi开发者_如何学Con Interactive Reporting ?

Create a new computed column and assign it a value of 1. Then, create another computed column which will have a cumulative sum of the previous computed column. The function to be used is Cume().