naming of dummy instances

Greetings Forum, 1st time poster :

I have been using this code to rename my dummy instances which works fine the first time I use this but subsequent runs report that "DUMMY0" already exists.  How to modify this to remember where it left off last time?

One idea I had was parsing the current cellview with 

zz=geGetEditCellView()

then: parsing that list with  zz~>instances~>names to find "DUMMY(x)" and then start at last x+1 value.

 procedure( nameDummyInst()
   let((cv cnt instList)
     cv=geGetWindowCellView()
     instList=selectedSet()
     labelLayer = list("text" "drawing")
     cnt = 0; initialize CNT

     foreach(inst instList
        temp1=pcExprToString( cnt )
        newInstName=strcat( "DUMMY",temp1 )
        inst~>baseName=newInstName
        cnt++;
        ) ;foreach
      ) ;let
) ;procedure

Thanks in advance

Malcolm