object Main {
  def main(args: Array[String]): Unit = {
    val n = readInt()
    val distance = Array.fill(n + 1)(-1)
    val que = new scala.collection.mutable.Queue[Int]
    que += 1
    distance(1) = 1
    while(!que.isEmpty){
      val x = que.dequeue()
      val y = x.toBinaryString.map(_.toInt - 48).sum
      for(z <- Array(x+y, x-y)){
        if(1 <= z && z <= n && distance(z) == -1){
          distance(z) = distance(x) + 1
          que += z
        }
      }
    }
    println(distance(n))
  }
}