Imports System

Module Program
    Sub Main(args As String())

        Dim tmp As String() = Split(Console.ReadLine(), " ")

        Dim A As Long = CLng(tmp(0))
        Dim B As Double = CDbl(tmp(1))
        Dim B2 As Long = Math.Floor((B * 100) + 0.5)
        Dim ans As Long = Math.Floor(((A * B2) / 100) + 0.5)

        Console.WriteLine(ans)

    End Sub

End Module
