// Learn more about F# at http://fsharp.org

open System

[<EntryPoint>]
let main argv =
  Console.ReadLine().Split([|' '; '.'|])
  |> fun xs -> int64 xs.[0] * ((int64 xs.[1]) * 100L + int64 xs.[2]) / 100L
  |> Console.WriteLine  
  0 // return an integer exit code
