#include <bits/stdc++.h>
using namespace std;

int main() {
  vector<long long> A(3);
  for (int i = 0; i < 3; ++i) cin >> A[i];
  long long K;
  cin >> K;
  sort(A.begin(), A.end());
  for (int i = 0; i < K; ++i) A.back() *= 2;
  cout << A[0] + A[1] + A[2] << endl;
}

#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <cstdio>
#include <cmath>
#include <tuple>
#include <iomanip>
#include <numeric>
#include <unordered_map>
#include <sstream>
#include<limits.h>
#include<float.h>
#include<list>
#include <array>
#include <complex>
#include<stdio.h>
#include<string.h>
#include <bitset>
// #include<assert.h>
#include<random>
using namespace std;
#define int long long

#define I32_MAX 2147483647
#define I64_MAX 9223372036854775807LL
#define I64_MAX2 1223372036854775807LL
#define INF I64_MAX2
#define MOD 1000000007
// #define MOD 998244353 
#define MEM_SIZE 100010
#define DEBUG_OUT true
#define ALL(x) (x).begin(), (x).end()

template<typename T> void DEBUG(T e){if(DEBUG_OUT == false)return; std::cout << e <<" ";}
template<typename T> void DEBUG(const std::vector<T>& v){if(DEBUG_OUT == false)return;for(const auto& e : v){std::cout<< e << " "; } std::cout << std::endl;}
template<typename T> void DEBUG(const std::vector<std::vector<T> >& vv){if(DEBUG_OUT == false)return;for(const auto& v : vv){ DEBUG(v); } }
template<class T,class... Ts> void DEBUG(T d, Ts... e){if(DEBUG_OUT == false)return;DEBUG(d);DEBUG(e...);}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; abort();}}
template< typename T1, typename T2 > inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template< typename T1, typename T2 > inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

//https://www.youtube.com/watch?v=RDaGj_ztNz4&feature=youtu.be

//-----CODE------//
void solve(void)
{
  int n;
  cin>>n;
  vector<int> a (n,0);
  for (int i = 0; i < n; i++)
  {
     cin>>a[i];
  }
  vector<vector<int> > dp (n+1,vector<int>(4,-1*INF));
  dp[0][0] = 0;
  int k = 1 +n%2;

  for (int i = 0; i < n; i++)
  {
    for (int j = 0; j < k+1; j++)
    {
      chmax(dp[i+1][j+1],dp[i][j]);
      int now = dp[i][j];
      if((i+j)%2 == 0) now += a[i];
      chmax(dp[i+1][j],now);
    }
    
  }
  cout<<dp[n][k]<<endl;
  
  

  return;
}

int32_t main(int32_t argc, const char *argv[])
{
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cout << std::fixed;
  std::cout << std::setprecision(11);
  solve();

  return 0;
}
