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

void Sum(int data[3],int K){
    
    data[2] *= 2;
    
    if(K == 1){
        int sum = 0;
        for(int i=0;i<3;i++) sum += data[i];
        cout << sum << endl;
    }
    else{
        Sum(data,K-1);
    }
}

int main(void){
    
    int data[3];
    int K;
    
    for(int i=0;i<3;i++) cin >> data[i];
    cin >> K;
    sort(data,data+3);
    
    Sum(data,K); 
    
}
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define F first
#define S second
#define pb push_back
#define mp make_pair
#define mod 1000000007
#define vlli vector<ll>
#define vi vector<int>
#define vs vector<string>
#define vplli vector< pair< ll,ll> >
#define plli pair< ll,ll >
#define vps vector< pair< string, string> >
#define vpi vector< pair< int, int> >
#define all(x) x.begin(), x.end()
#define fast ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define forn(i,a,n) for(ll i=a;i<n;i++)
#define scan(arr,a,n) for(ll i=(a);i<(n);i++)cin>>(arr)[i];
#define print(arr,a,n) for(ll i=(a);i<(n);i++)cout<<(arr)[i]<<" ";

ll add(ll x, ll y) {ll res = x + y; return (res >= mod ? res - mod : res);}
ll mul(ll x, ll y) {ll res = x * y; return (res >= mod ? res % mod : res);}
ll sub(ll x, ll y) {ll res = x - y; return (res < 0 ? res + mod : res);}
ll power(ll x, ll y) {ll res = 1; x %= mod; while (y) {if (y & 1)res = mul(res, x); y >>= 1; x = mul(x, x);} return res;}
ll mod_inv(ll x) {return power(x, mod - 2);}


int main(){
	fast;
    #ifndef ONLINE_JUDGE
    freopen("input1.txt","r",stdin);
    freopen("output1.txt","w",stdout);
    #endif
	long double n, m, x;
	cin>>n>>m>>x;
	cout<<(ll)ceil(x/max(n, m));
}