Module _20191116

    Sub Main()
        'https://atcoder.jp/contests/abc108/tasks/abc108_a

        Dim iNumber As Integer = Console.ReadLine()

        Dim iKisuuCount As Integer = 0
        Dim iGusuuCount As Integer = 0

        For i As Integer = 1 To iNumber

            If i Mod 2 = 0 Then
                iGusuuCount += 1
            Else
                iKisuuCount += 1
            End If

        Next

        Console.WriteLine(iGusuuCount * iKisuuCount)

    End Sub

End Module