import java.util.*;

class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		
		int yuki = sc.nextInt(); int huri = sc.nextInt();
		int n = sc.nextInt();
		HashMap<Integer, Integer> map = new HashMap<>();
		for (int i=0; i<n; i++) {
			int temp = sc.nextInt();
			map.put(temp, map.getOrDefault(temp,0)+1);
		}
		
		int ans = 0;
		
		for (Map.Entry<Integer, Integer> e: map.entrySet()) {
			ans += (e.getValue()-1) * (yuki+huri);
        }
		
		System.out.println(ans);
	}
}