How to combine Where and Right in Formula

Hi , i need SAP to return the numeric results when the last letter of a Text string is "L".

I tried with this formula: =If(Right([Betaler];1)="L") Then [Number of accounts] Else 0,

It works fine as a Dimension, but i need to include the numbers in a report as a Measure, and it fails with #MULTIVALUE

Kind regards Daniel