import math._

object Main {

  def calc(a: Int, b: Int, c: Int, xs: Array[Int]): Int = {
    val dp = Array.fill(31)(Integer.MAX_VALUE / 10)
    for (i <- Array(a, b, c)) {
      dp(i) = 1
      for (j <- i+1 to 30) {
        dp(j) = min(dp(j), dp(j-i) + 1)
      }
    }

    xs.map { e => dp(e) }.sum
  }

  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)
    val xs = Array.fill(4)(sc.nextInt)

    var ans = Integer.MAX_VALUE
    for (i <- 1 to 30) {
      for (j <- i+1 to 30) {
        for (k <- j+1 to 30) {
          ans = min(ans, calc(i, j, k, xs))
        }
      }
    }

    println(ans)
  }
}