/* define a recursive function */
let

function printint(i: int) =
  let function f(i:int) = if i>0 
	     then (f(i/10); print(chr(i-i/10*10+ord("0"))))
   in if i<0 then (print("-"); f(-i))
      else if i>0 then f(i)
      else print("0")
  end

/* calculate n! */
function nfactor(n: int): int =
		if  n = 0 
			then 1
			else n * nfactor(n-1)

in
	(printint(nfactor(6)); print("\n"))
end