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 roop = int.Parse(Console.ReadLine());
        
        var roomList = new List<string>();
        
        for(var i = 0; i < roop; i++){
            roomList.Add(Console.ReadLine());
        }
        
        var duplicate = roomList.Count - roomList.Distinct().Count();
        
        Console.WriteLine(duplicate * cost);
    }
}