1070

// PATn.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

int main()
{
    unsigned n;
    cin >> n;

    vector<unsigned> data;
    for (unsigned i = 0; i < n; ++i)
    {
        unsigned tmp;
        cin >> tmp;
        data.push_back(tmp);
    }

    sort(data.begin(), data.end());

    double length = data[0]*1.0/2.0+data[1]*1.0/2.0;
    for (unsigned i=2;i<data.size();++i)
    {
        length = length / 2.0 + data[i]*1.0 / 2.0;
    }

    cout << static_cast<unsigned>(length);

    system("pause");
    return 0;
}