//
//  main.swift
//  TestSpace for AtCoder
//
//  Created by Koichi Okai on 2020/06/25.
//  Copyright © 2020 Koichi Okai. All rights reserved.
//

func readInts() -> [Int] {
    return readLine()!.split(separator: " ").map { Int($0)! }
}

func main() {
    let lrd = readInts()
    
    let L = lrd[0]
    let R = lrd[1]
    let d = lrd[2]
    
    let a = (L...R).filter { $0 % d == 0 }.count
    
    print(a)
}

main()
