fun fact 1 = 1
  | fact n = 
    n * fact (n - 1)


fun readInt () =
    valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn)


val () =
    let
        val trick = Word.fromInt(readInt ())
        val treat = Word.fromInt(readInt ())

        val ans = fact (Word.toLargeInt(Word.orb(trick, treat)))
    in
        print (LargeInt.toString ans ^ "\n")
    end