Imports System

Module Program
    Sub Main(args As String())

        Dim NXT() As Integer = Console.ReadLine().Split(" ").Select(Function(x) Integer.Parse(x)).ToArray()

        Dim kaisu As Integer = NXT(0) \ NXT(1)
        If NXT(0) Mod NXT(1) <> 0 Then
            kaisu += 1
        End If

        Dim ans As Integer = kaisu * NXT(2)

        Console.WriteLine(ans)

    End Sub
End Module
