import kotlin.math.*

fun main() {
    val x = readLine()!!.split(" ").map { it.toInt() }
    val L = x[0]
    val R = x[1]
    val d = x[2]
    var ans=0
    for (i in L..R){
        if(i%d == 0){
            ans++
        }
    }
    print(ans)
}