
--{-# LANGUAGE StandaloneDeriving #-}
--{-# LANGUAGE BangPatterns #-}

module Main where

import Debug.Trace
--import Data.List
--import Data.Char
--import qualified Data.Set.Strict as Set
--import qualified Data.Map.Strict as Map

main :: IO ()
main = do
  [l, r, d] <- map read . words <$> getLine
  --a `traceShow`
  print $ solve l r d

solve :: Int -> Int -> Int -> Int
solve l r d = length . filter ((== 0) . (`mod` d)) $ [l..r]
