import java.util.*;

class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int A = Integer.parseInt(sc.next());
      	int B = Integer.parseInt(sc.next());
      	int C = Integer.parseInt(sc.next());
      	int K = Integer.parseInt(sc.next());
        int[]hako = {A,B,C};
      
      	Arrays.sort(hako);
      int max = hako[2];
      	for(int i=0;i<K;i++){
          max = max *2;
        }
      max = max + hako[0] + hako[1];
      System.out.print(max);
      
      
      
    }
}
/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