#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <stdio.h>
using namespace std;
#define int long long
int MOD = 1000000007;
signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int A, B;
	cin >> A >> B;
	int N;
	cin >> N;
	vector<int> C(1000, 0);
	int a;
	for (int i = 0; i < N; i++) {
		cin >> a;
		C[a]++;
	}
	int res = 0;
	for (int i = 0; i < 1000; i++) {
		res += max((int)0, (A + B)*(C[i] - 1));
	}
	cout << res << endl;
}