Performance issue for One of my MDX Code

Hi Friends,

I was writing one simple code it was running about 1 min to get the required result.

Can anyone have a look how to improve the performance of this Query

WITH
SET dates_forVoidEOTStartDateVUN  AS

Nonempty(
{
NULL
:
[VoidProgressEOTStartDate].[CalendarYearByMonth].[YYYYMMDD].&[2013-05-10T00:00:00]
},[Measures].[CountVUNStarted]
)	
MEMBER measures.VUNStartedwithTimePeriod AS
     AGGREGATE ({
     dates_forVoidEOTStartDateVUN 
                } 
                ,[Measures].[CountVUNStarted]) 

SET VPRNsEndingInPeriod AS
	[VoidProgress].[VPRN].[ALL].children

MEMBER [VoidProgress].[VPRN].[Total] AS
	aggregate(VPRNsEndingInPeriod,measures.currentmember)
SELECT
{

 measures.VUNStartedwithTimePeriod 
} 
DIMENSION PROPERTIES
MEMBER_CAPTION
,MEMBER_UNIQUE_NAME

ON 0,
{
[VoidProgress].[VPRN].[Total]

} ON 1

FROM [Cube]

Thanks in advance