func main() {
    let input = readLine()!.split(separator: " ").map {Int($0)!}
    let input_L = input[0]
    let input_R = input[1]
    let input_d = input[2]
    var counts = 0
    for it in input_L...input_R {
        if it % input_d == 0 {
            counts += 1
        }
    }
    print(counts)
}

main()