#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=35;
int a[N];
int sum;
signed main()
{
    int i=0;
    while(cin>>a[i]!=EOF)
    {
        sum+=a[i];
        i++;
    }
    sum=pow(2,(i-1))*sum;
    cout<<sum<<endl;
    return 0;
}