#include <iostream>
#include <vector>
#include <climits>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include <string>
#include <bitset>
#include <utility>
#include <numeric>
#include <queue>
#include <stack>

using ll = long long;
using namespace std;

constexpr int MOD = 1e9 + 7;
constexpr ll MOD_LL = ll(1e9 + 7);

int main(void) {
	int a, b, c, k;
	cin >> a >> b >> c >> k;
	
	vector<int> x = {a, b, c};
	int ans = 0;
	for(int i = 0; i < k; ++i) {
		sort(x.begin(), x.end());
		x[2] *= 2;
	}
	
	cout << accumulate(x.begin(), x.end(), 0) << endl;
	
	return 0;
}


#pragma GCC optimize ("O3")

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include <prettyprint.hpp>
#define debug(...)  cerr << "[" << #__VA_ARGS__ << "]: ", d_err(__VA_ARGS__);
#else
#define debug(...) 83;
#endif

void d_err() {
    cerr << endl;
}

template <typename H, typename... T>
void d_err(H h, T... t) {
    cerr << h << " ";
    d_err(t...);
}

template <typename T>
void print(T x) {
    cout << x << endl;
}

#define ALL(x) (x).begin(), (x).end()
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define REP(i, n) FOR(i, 0, n)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define bcnt __builtin_popcountll

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<ll,ll> Pll;
typedef pair<int,int> Pin;

ll INF = 1e16;
int inf = 1e9;
ll MOD = 1e9+7;


int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    vi v(3);
    REP(i, 3) cin >> v[i];

    sort(ALL(v), greater<>());

    int k;
    cin >> k;

    print(v[0] * (1 << k) + v[1] + v[2]);


}
