using System;
using System.Collections.Generic;
using System.Linq;

public class Amatsuki{
    public static void Main(){
        var cost = int.Parse(Console.ReadLine());
        cost += int.Parse(Console.ReadLine());
        
        var roomCount = int.Parse(Console.ReadLine());
        
        var roomList = new List<string>();
        
        for(var i = 0; i < roomCount; i++){
            var newRoom = Console.ReadLine();
            if(roomList.Contains(newRoom)){
                roomList.Add(newRoom);
            }
        }
        
        Console.WriteLine(cost * (roomCount - roomList.Count));
    }
}