or one of chars. 
 
   The function returns the index of the last character of str 
   at or before index start that is in the collection chars. 
 </PRE>
<h4><a name="Detailed_Input">Detailed_Input</a></h4>
<PRE>
 
   str        is any character string. 
 
   chars      is a character string containing a collection 
              of characters.  Spaces in chars are significant,
              including trailing blanks.  The order in which
              characters are listed is not significant.
 
   start    