Copyright 2004 Ray Ontko & Co.  All rights reserved.

begin-setup
create-array
   name=stack
   size=100
   field=param:number
   field=tmp1:number
end-setup


begin-program
input $answer 'Which element in the sequence'
move $answer to #answer
do f(#answer,#result)
show #result edit 999999
end-program

begin-procedure f(#param, :#return)
add 1 to #_call_level
if #param < 2
   move 1 to #return
else
   subtract 1 from #param
   put #param into stack(#_call_level) param
   do f(#param, #tmp1)
   get #param from stack(#_call_level) param
   subtract 1 from #param
   put #param #tmp1 into stack(#_call_level) param tmp1
   do f(#param, #tmp2)
   get #param #tmp1 from stack(#_call_level) param tmp1
   let #return = #tmp1 + #tmp2
end-if
subtract 1 from #_call_level
end-procedure f