How to write a MapPageRoute in asp.net 4.0

I hope to map the url
http://www.a.com/1 =>  ttp://www.a.com/RunProgram.aspx?ProgramID=1
http://www.a.com/2 =>  ttp://www.a.com/RunProgram.aspx?ProgramID=2
http://www.a.com/3 =>  ttp://www.a.com/RunProgram.aspx?ProgramID=3
How to write the MapPageRoute in asp.net 4.0?
routes.MapPageRoute("", "{ProgramID}", "~/RunProgram.aspx") seems there are some problem!
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