import scala.io.StdIn

object Problem172 {

  def proc(x: Int, y: Int, r: Int): Int = {
    // 1:1:sqrt(2)
    val len = r / Math.sqrt(2)

    // y = ax + b -> b = y - (-1x) -> b = y + x
    val dist = x.abs + len + y.abs + len
    dist.ceil.toInt
  }

  def main(args: Array[String]) {
    val xyr = StdIn.readLine().split(" ").map(_.toInt)
    val result: Int = proc(xyr(0), xyr(1), xyr(2))
    println(result)
  }
}