object Main extends App {
  val inputs: Seq[String] = scala.io.Source.stdin.getLines().toList
  val n = inputs.head.toInt

  println(solve(n))

  def solve(n: Int): String = {
    var dog = n
    val str  = "-abcdefghijklmnopqrstuvwxyz"
    val base = 26
    var name = ""

    while(dog != 0) {
      val p = dog % base
      dog = dog / base
      name = name + str(p.toInt)
    }
    name.reverse
  }
}