import java.util.*;
import java.util.stream.Stream;
import java.time.*;
import java.time.format.*;

public class No586 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
		int lost = sc.nextInt() + sc.nextInt();
		int n = sc.nextInt();
		int[] r = new int[n];
		int count = 0;
		for(int i = 0; i < n ; i++) {
			r[i] = sc.nextInt();
		}
		Arrays.sort(r);
		for(int i = 0; i < n - 1; i++) {
			if(r[i] == r[i+1]) {
				count++;
			}
		}
		System.out.println(count * lost);
	}
}