ural1025

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;


class Program
{
    static void Main(string[] args)
    {
        problem p = new problem();
    }
}

class RTIO
{
    static string bufferStr = "";
    public static int GetInt()
    {
        if (bufferStr.Length == 0)
        {
            bufferStr = Console.ReadLine();
        }
        int index = bufferStr.IndexOf(' ');
        if (index < 0) index = bufferStr.Length;

        int res = int.Parse(bufferStr.Substring(0, index));
        if (index != bufferStr.Length)
        {
            bufferStr = bufferStr.Remove(0, index + 1);
        }
        else
        {
            bufferStr = "";
        }
        return res;
    }
    public static string GetString()
    {
        if (bufferStr.Length == 0)
        {
            bufferStr = Console.ReadLine();
        }
        string res = bufferStr;
        bufferStr = "";
        return res;
    }
}

class problem
{
    public problem()
    {
        int n = RTIO.GetInt();
        int[] groups = new int[n];
        for (int i = 0; i < n; i++)
        {
            groups[i] = RTIO.GetInt();
        }
        Array.Sort(groups);
        int res = 0;
        for (int i = 0; i < n / 2 + 1; i++)
        {
            res += groups[i] / 2 + 1;
        }
        Console.WriteLine(res);
    }
}