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

fun readReal () =
    valOf (TextIO.scanStream Real.scan TextIO.stdIn)


val () =
    let
        val w = readInt ()
        val z = readInt ()
        val b = readReal ()

        val ans = Real.floor ((Real.fromInt (w + z)) * (1.0 + b))
    in
        print (Int.toString ans ^ "\n")
    end