F param Fn
  if Fn = 0
     1 R
  else
     (Fn-1) nm1
     save Fn
     call F nm1
     result Fr
     save Fr
     call M Fr
     result Mr
     restore Fr
     restore Fn
     (Fn-Mr) R
  endif
  return R

M param Mn
  if Mn = 0
     0 R
  else
     (Mn-1) nm1
     save Mn
     call M nm1
     result Mr
     save Mr
     call F Mr
     result Fr
     restore Mr
     restore Mn
     (Mn-Fr) R
  endif
  return R

start

 i
 if i <= 19
    call F i
    result res
    " $s res ' '" $s
    + i
    goif
 endif
 $s []
 $s

 i
 if i <= 19
    call M i
    result res
    " $s res ' '" $s
    + i
    goif
 endif
 $s []