#include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; (i) < (int)(n); ++ (i))
#define REP3(i, m, n) for (int i = (m); (i) < (int)(n); ++ (i))
#define REP_R(i, n) for (int i = (int)(n) - 1; (i) >= 0; -- (i))
#define REP3R(i, m, n) for (int i = (int)(n) - 1; (i) >= (int)(m); -- (i))
#define ALL(x) ::std::begin(x), ::std::end(x)
using namespace std;


int64_t solve(int n, int64_t k, int64_t x, int64_t y, const vector<int64_t> & a) {
    vector<int64_t> b(n);
    REP (i, n) {
        b[i] = (a[i] - 1 + k - 1) / k;
    }
    sort(ALL(b));
    reverse(ALL(b));

    int64_t l = y / x;
    if (l >= n) {
        return x * accumulate(ALL(b), 0ll);
    } else {
        int64_t ans = y * b[l];
        REP (i, l) {
            ans += x * (b[i] - b[l]);
        }
        return ans;
    }
}

// generated by online-judge-template-generator v4.1.1 (https://github.com/kmyk/online-judge-template-generator)
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    constexpr char endl = '\n';
    int64_t N;
    int64_t K, X, Y;
    cin >> N;
    vector<int64_t> A(N);
    cin >> K >> X >> Y;
    REP (i, N) {
        cin >> A[i];
    }
    auto ans = solve(N, K, X, Y, A);
    cout << ans << endl;
    return 0;
}