import scala.io.StdIn.*

def calcFactorInFactorial(n: Long, m: Long): Long =
  n match
    case 0L => 0
    case _ => n / m + calcFactorInFactorial(n / m, m)

@main def main =
  val Array(n, k, m) = readLine().split(' ').map(_.toLong)
  val cFactor = calcFactorInFactorial(n, m) - calcFactorInFactorial(k, m) - calcFactorInFactorial(n - k, m)
  println(cFactor)