using System.Numerics;

public class Program
{
    public static void Main()
    {

        int num = int.Parse(Console.ReadLine() ?? string.Empty);
        string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;

        int[] ints = str.Select(int.Parse).ToArray();
        Array.Sort(ints);
        int count = 0;
        for(int i = num - 1; i >= 1;i--)
        {
            if (ints[i] -1 != ints[i-1])
            {
                count += ints[i];
            }
        }
        Console.WriteLine(count + ints[0]);

    }
}