
Imports System.Console
Module Module1
    Dim L, R, d As Int64
    Dim ans As Int64
    Sub Main()
        Dim s() As String = ReadLine().Split
        L = s(0)
        R = s(1)
        d = s(2)
        For i = L To R
            If i Mod d = 0 Then
                ans += 1
            End If
        Next
        WriteLine(ans)
    End Sub
End Module
