import java.util._

object Main {
  def main(args:Array[String]) = {
    val sc = new java.util.Scanner(System.in)
    val a = sc.nextInt
    val b = sc.nextInt
    val c = sc.nextInt
    val list = Array(a, b, c)
    val max = list.max
    var ans = max * 9
    for(v <- list) {
      ans += v
    }
    println(ans)
  }
}