import java.util.*;

class Main{
	
	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);
		int A[] = new int[3];
		for(int n=0;n<3;n++){
			A[n] = sc.nextInt();
		}
		int K = sc.nextInt();

		long v = 0;
		if(A[0] >= A[1] && A[0] >= A[2]){
			v += A[0] * Math.pow(2,K);
			v += A[1]+A[2];
		}
		else{
			if(A[1] >= A[0] && A[1] >= A[2]){
				v += A[1] * Math.pow(2,K);
				v += A[0]+A[2];
			}
			else{
				if(A[2] >= A[0] && A[2] >= A[1]){
					v += A[2] * Math.pow(2,K);
					v += A[1]+A[0];
				}
			}
		}
		

		System.out.println(v);
	}
}
/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