Distinct count

Hi all,Prolly easy question, but for some reason the query below does not return the distinct count but just the count. Should be 16 but it's retruning 17. Any help? :)WITH SET [MySet] ASNONEMPTY(FILTER([Geography].[City].[City].Members,instr(left([Geography].[City].currentmember.name,1), 'A') > 0),[Measures].[Internet Order Count])MEMBER [Measures].[CountMembers] ASDISTINCTCOUNT([MySet])//why not distinct?SELECT {[Measures].[Internet Order Count],[Measures].[CountMembers]}ON COLUMNS,[MySet]ON ROWSFROM [Adventure Works]