using System;
using System.Collections.Generic;

namespace lecture
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            int P = int.Parse(Console.ReadLine());
            P += int.Parse(Console.ReadLine());

            int N = int.Parse(Console.ReadLine());

            Dictionary<string, int> roomNumber = new Dictionary<string,int>();

            for (int i = 0; i < N; i++)
            {
                string R = Console.ReadLine();
                if (roomNumber.ContainsKey(R))
                {
                    roomNumber[R]++;
                }
                else
                {
                    roomNumber[R] = 1;
                }
            }

            int count = 0;

            foreach (int cnt in roomNumber.Values)
            {
                if (cnt > 1)
                {
                    count += cnt - 1;
                }
            }

            Console.WriteLine(count * P);
        }
    }
}