P2415 集合求和

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

int main(){
    long long  sum = 0;
    int num = 0;
    int t;
    while(cin >> t){
        sum += t;
        num++;
    }
    
    cout << (long long)(sum*pow(2 , num -1)); 
    return 0;
}