import java.util.*;
 
class Main{
	public static void main(String args[]) throws Exception{
		Scanner sc = new Scanner(System.in);
    int a= sc.nextInt();
    int b= sc.nextInt();
    int c= sc.nextInt();
    int d= sc.nextInt();

    int max = a;
    int otherSum = b+c;

    if(max < b){
      max = b;
      otherSum = a+c;
    }

    if(max < c){
      max = c;
      otherSum = a+b;
    }

    for(int i=0; i<d; i++){
  		max = max*2;
  	}

    int sum = max + otherSum;
    System.out.println(sum);
	}
}
/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