#include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < (n); i++)
#define REP1(i, n) for(int i = 1; i <= (n); i++)
#define REPD(i,a,b) for (int i=(a);i<(b);i++)
#define ALL(v) (v).begin(), (v).end()
using namespace std;
typedef long long ll;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef set<int> si;
typedef vector<si> vsi;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<int, int> pi;
typedef queue<int> qi;
typedef queue<pi> qpi;
typedef pair<ll, ll> pll;
typedef queue<pll> qpll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
const int mod = 1000000007;
const int INF = 1001001001;
// 小数点　<< fixed << setprecision(0) <<
// sort降順　sort(ALL(),greater<int>());
// 円周率　M_PI
// 文字判定　isupper islower
// 文字変換　
// 順列　do {} while(next_permutation(ALL(X)));
// 最大値　LLONG_MAX
// a内でx以上　auto iter = lower_bound(ALL(a), x);
// a内でxより大きい　auto iter = upper_bound(ALL(a), x);
int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};
struct edge {
    int from; //出発点
    int to;   //到達点
    int cost; //移動コスト
};
typedef struct edge se;
typedef vector<edge> ve;
unsigned Euclidean_gcd(unsigned a, unsigned b) {
  if(a < b) return Euclidean_gcd(b, a);
  unsigned r;
  while ((r=a%b)) {
    a = b;
    b = r;
  }
  return b;
}

vpll PrimeFactorization(ll n) {
  vpll res;
  for (ll i=2; i*i<=n; i++) {
    if(n%i!=0) continue;
    ll ex=0;
    while(n%i==0) {
      ex++;
      n/=i;
    }
    res.push_back(pll(i,ex));
  }
  if(n!=1) res.push_back(pll(n,1));
  return res;
}

int main() {
  int k;
  vi a(3);
  cin >> a[0] >> a[1] >> a[2] >> k;
  sort(ALL(a));
  int ans=a[0]+a[1]+a[2]*pow(2,k);
  cout << ans << endl;
  return 0;
}

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

const ll LINF = 1e18;
const int INF = 1e9;
const ll MOD = 1000000007;

int main(){

    int a, b, c, k;
    cin >> a >> b >> c >> k;

    for(int i = 0; i < k; i++){
        if(a < b){
            if(b < c) c *= 2;
            else b *= 2;
        }
        else{
            if(a < c) c *= 2;
            else a *= 2;
        }
    }
    cout << a + b + c << endl;
    
    return 0;
}