//

fun main() {
    aising2020a()
}

fun aising2020a() {
    val (l, r, d) = readLine()!!.split(" ").map {it.toInt()}
    var count = 0
    var k = 1
    while (k * d <= r) {
        if (k * d in l..r) count++
        k++
    }
    println(count)
}
