using System;

public class Hello
{
    public static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        var bsum = 0;
        var ans = 0;
        for (int i = 0; i < n; i++)
        {
            var b = a[i] / 2;
            ans = Math.Max(ans, a[i] - b);
            bsum += b;
        }
        Console.WriteLine(ans + bsum);
    }
}