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

fun readStr () =
    let
        fun scan reader stream = SOME (StringCvt.splitl (not o Char.isSpace) reader (StringCvt.skipWS reader stream))
    in
        valOf (TextIO.scanStream scan TextIO.stdIn)
    end


val () =
    let
        val v = readStr ()
        val t = readInt ()

        val vv = valOf (Int.fromString (String.substring (v, 2, String.size v - 2)))
        val ans = (vv * t) div 10000
    in
        print (Int.toString ans ^ "\n")
    end