import java.util.Scanner;
class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int[] number = new int[3];
    int sum = 0;
    
    for(int i=0;i<3;i++){
      number[i] = sc.nextInt();
      sum += number[i];
    }
    int K = sc.nextInt();
    int max = number[0];
    
    for(int j=0;j<2;j++){
      if(number[j+1]>number[j]){
        max = number[j+1];
      }
    }
    int answer = (int)(sum-max+max*Math.pow(2,K));
    System.out.println(answer);
  }
}
    
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz