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 = CLng(B * 100)
        Dim ans As Long = Math.Floor((A * B2) \ 100)

        Console.WriteLine(ans)

    End Sub

End Module
