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 num = int.Parse(Console.ReadLine() ?? string.Empty);
        int change = int.Parse(Console.ReadLine() ?? string.Empty);
        int yoyaku = int.Parse(Console.ReadLine() ?? string.Empty);

        List<int> roomlist = new List<int>();
        for (int i = 0; i < yoyaku; i++)
        {
            int room = int.Parse(Console.ReadLine() ?? string.Empty);
            roomlist.Add(room);
        }
        roomlist.Sort();

        int money = 0;
        for (int i = roomlist.Count - 1; i >= 1;i--)
        {
            if (roomlist[i] == roomlist[i-1])
            {
                roomlist.RemoveAt(i);
                money += (num + change);
            }
        }
        Console.WriteLine(money);
    }
}