#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
#define all(x) x.begin(),x.end()
#define rep(i,j,n) for (long long i = j; i < (long long)(n); i++)
#define _GLIBCXX_DEBUG
#define MOD 1000000007
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
//name[i][j]-> vvl name(i,vl(j))
//map<int,int>mp
//余りを切り上げる =>  (a + b - 1) / b 

signed main(){
	int a,b,c; cin>>a>>b>>c;
	int k; cin>>k;
	int d=max({a,b,c});
	//d*=2;
	rep(i,0,k) d*=2;
	cout<<(a+b+c-max({a,b,c})+d);
	
	
	return 0;
}
#include <bits/stdc++.h>
#pragma GCC optimize("O3")

#define fi first
#define se second
#define em emplace
#define eb emplace_back
#define mp make_pair
#define pi pair<int,int>
#define vi vector<int>
#define vpi vector<pair<int,int>>
#define vll vector<ll>
#define vpll vector<pair<ll,ll>>
#define endl '\n'

#define si(v) int((v).size())
#define all(v) (v).begin(), (v).end()
#define rep(i, n) for (ll i = 0; i < (ll)(n); ++i) 
#define rep2(i, n, m) for (ll i = n; i <= (ll)(m); ++i)
#define rep3(i, n, m) for (ll i = n; i >= (ll)(m); --i)

template<class T, class U> bool chmax(T &a, U b) { if (a < b) a = b; return true; }
template<class T, class U> bool chmin(T &a, U b) { if (a > b) a = b; return true; }

using ll = long long;
using ld = long double;
using namespace std;

constexpr ll MOD = 1000000007;

signed main()
{
  cout << fixed << setprecision(20);
  ios::sync_with_stdio(false);
  cin.tie(0);

  vi d(3);
  rep(i, 3) cin >> d[i];

  int k; cin >> k;
  sort(all(d));

  rep(i, k) d[2] *= 2;

  cout << accumulate(all(d),0) << endl;

  return (0);
}
