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 duplicate = 0;
        var check = "";
        
        for(var i = 0; i < roomCount; i++){
            var newRoom = "_" + Console.ReadLine();
            if(check.IndexOf(newRoom) < 0){
                check += newRoom;
            } else{
                duplicate++;
            }
        }
        
        Console.WriteLine(cost * duplicate);
    }
}