output_description: Print the largest possible sum of the integers written on the blackboard after
  K operations by E869220.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B C
      K
attempt: #!/usr/bin/env python3
  
  import sys
  
  # import time
  # import math
  # import numpy as np
  # import scipy.sparse.csgraph as cs            # csgraph_from_dense(ndarray, null_value=inf), bellman_ford(G, return_predecessors=True), dijkstra, floyd_warshall
  # import random                                # random, uniform, randint, randrange, shuffle, sample
  # import string                                # ascii_lowercase, ascii_uppercase, ascii_letters, digits, hexdigits
  # import re                                    # re.compile(pattern) => ptn obj; p.search(s), p.match(s), p.finditer(s) => match obj; p.sub(after, s)
  # from bisect import bisect_left, bisect_right # bisect_left(a, x, lo=0, hi=len(a)) returns i such that all(val<x for val in a[lo:i]) and all(val>-=x for val in a[i:hi]).
  # from collections import deque                # deque class. deque(L): dq.append(x), dq.appendleft(x), dq.pop(), dq.popleft(), dq.rotate()
  # from collections import defaultdict          # subclass of dict. defaultdict(facroty)
  # from collections import Counter              # subclass of dict. Counter(iter): c.elements(), c.most_common(n), c.subtract(iter)
  # from datetime import date, datetime          # date.today(), date(year,month,day) => date obj; datetime.now(), datetime(year,month,day,hour,second,microsecond) => datetime obj; subtraction => timedelta obj
  # from datetime.datetime import strptime       # strptime('2019/01/01 10:05:20', '%Y/%m/%d/ %H:%M:%S') returns datetime obj
  # from datetime import timedelta               # td.days, td.seconds, td.microseconds, td.total_seconds(). abs function is also available.
  # from copy import copy, deepcopy              # use deepcopy to copy multi-dimentional matrix without reference
  # from functools import reduce                 # reduce(f, iter[, init])
  # from functools import lru_cache              # @lrucache ...arguments of functions should be able to be keys of dict (e.g. list is not allowed)
  # from heapq import heapify, heappush, heappop # built-in list. heapify(L) changes list in-place to min-heap in O(n), heappush(heapL, x) and heappop(heapL) in O(lgn).
  # from heapq import nlargest, nsmallest        # nlargest(n, iter[, key]) returns k-largest-list in O(n+klgn).
  # from itertools import count, cycle, repeat   # count(start[,step]), cycle(iter), repeat(elm[,n])
  # from itertools import groupby                # [(k, list(g)) for k, g in groupby('000112')] returns [('0',['0','0','0']), ('1',['1','1']), ('2',['2'])]
  # from itertools import starmap                # starmap(pow, [[2,5], [3,2]]) returns [32, 9]
  # from itertools import product, permutations  # product(iter, repeat=n), permutations(iter[,r])
  # from itertools import combinations, combinations_with_replacement
  # from itertools import accumulate             # accumulate(iter[, f])
  # from operator import itemgetter              # itemgetter(1), itemgetter('key')
  # from fractions import gcd                    # for Python 3.4 (previous contest @AtCoder)
  
  
  def main():
      mod = 1000000007  # 10^9+7
      inf = float("inf")  # sys.float_info.max = 1.79...e+308
      # inf = 2 ** 64 - 1             # (for fast JIT compile in PyPy) 1.84...e+19
      sys.setrecursionlimit(10**6)  # 1000 -> 1000000
  
      def input():
          return sys.stdin.readline().rstrip()
  
      def ii():
          return int(input())
  
      def mi():
          return map(int, input().split())
  
      def mi_0():
          return map(lambda x: int(x) - 1, input().split())
  
      def lmi():
          return list(map(int, input().split()))
  
      def lmi_0():
          return list(map(lambda x: int(x) - 1, input().split()))
  
      def li():
          return list(input())
  
      a, b, c = mi()
      k = ii()
      print(a + b + c + (pow(2, k) - 1) * c)
  
  
  if __name__ == "__main__":
      main()
  
problem_description: Statement
  
  There are three positive integers A, B and C written on a blackboard. E869120
  performs the following operation K times:
  
    * Choose one integer written on the blackboard and let the chosen integer be n. Replace the chosen integer with 2n.
  
  What is the largest possible sum of the integers written on the blackboard
  after K operations?
samples: [{"input": "5 3 11\n    1", "output": "30\n    \n\nIn this sample, 5, 3, 11 are initially written on the blackboard, and E869120\ncan perform the operation once.  \nThere are three choices:\n\n  1. Double 5: The integers written on the board after the operation are 10, 3, 11.\n  2. Double 3: The integers written on the board after the operation are 5, 6, 11.\n  3. Double 11: The integers written on the board after the operation are 5, 3, 22.\n\nIf he chooses 3., the sum of the integers written on the board afterwards is 5\n+ 3 + 22 = 30, which is the largest among 1. through 3.\n\n* * *"}, {"input": "3 3 4\n    2", "output": "22\n    \n\nE869120 can perform the operation twice. The sum of the integers eventually\nwritten on the blackboard is maximized as follows:\n\n  * First, double 4. The integers written on the board are now 3, 3, 8. \n  * Next, double 8. The integers written on the board are now 3, 3, 16. \n\nThen, the sum of the integers eventually written on the blackboard is 3 + 3 +\n16 = 22."}]