import Foundation

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

func main(){
    let lrd = readInts()
    let (l,r,d) = (lrd[0], lrd[1], lrd[2])
    var ans = 0
    for i in l...r {
        if i % d == 0 {
            ans += 1
        }
    }
    
    print(ans)
}
main()
