fun readLargeInt () =
    valOf (TextIO.scanStream (LargeInt.scan StringCvt.DEC) TextIO.stdIn)


        
val () =
    let
        val n = readLargeInt ()
        val m = readLargeInt ()

        val ans = ((n div (Int.toLarge 1000)) div m) * (Int.toLarge 1000)
    in
        print (LargeInt.toString ans ^ "\n")
    end