fn.def ackermann(m,n)
   if m = 0 then
      fn.rtn n+1
   else
      if n = 0 then
         fn.rtn ackermann(m-1,1)
      else
         fn.rtn ackermann(m-1,ackermann(m,n-1))
      endif
   endif
fn.end

for m = 0 to 4
   for n = 0 to 4
      print m ; " " ; n ; " " ; ackermann(m,n)
   next n
next m