#include <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
	int64_t k, x, y; cin >> k >> x >> y;
	int64_t a[n];
	int64_t sum = 0;
	for(int i = 0; i < n; ++i) {
		cin >> a[i];
		--a[i];
		a[i] = (a[i] + k - 1) / k;
		sum += a[i];
	}
	sort(a, a + n);
	int64_t ans = sum * x;
	int64_t cnt = 0;
	for(int i = 0; i < n; ++i) {
		cnt = a[i];
		sum -= a[i];
		// cout << cnt << " " << sum << '\n';
		int64_t tmp = (sum - cnt * (n - i - 1)) * x + cnt * y;
		// cout << tmp << '\n';
		ans = min(ans, tmp);
	}
	cout << ans << '\n';
	return 0;
}