#include using namespace std; using lint = long long int; using pint = pair; using plint = pair; struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template void ndarray(vector &vec, int len) { vec.resize(len); } template void ndarray(vector &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); } template bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; } template bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; } template pair operator+(const pair &l, const pair &r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair &l, const pair &r) { return make_pair(l.first - r.first, l.second - r.second); } template istream &operator>>(istream &is, vector &vec){ for (auto &v : vec) is >> v; return is; } template ostream &operator<<(ostream &os, const vector &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const deque &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const pair &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; } template ostream &operator<<(ostream &os, const map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } #define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl; /* #include #include #include using namespace __gnu_pbds; // find_by_order(), order_of_key() template using pbds_set = tree, rb_tree_tag, tree_order_statistics_node_update>; template using pbds_map = tree, rb_tree_tag, tree_order_statistics_node_update>; */ int main() { int N, K, X, Y; cin >> N >> K >> X >> Y; chmin(X, Y); vector A(N); cin >> A; REP(i, N) A[i] = (A[i] + K - 2) / K; sort(ALL(A)); lint e = (Y + X - 1) / X; chmin(e, N); lint h = (e == N ? 0 : A[N - e]); lint ret = Y * h; FOR(i, N - e, N) ret += X * (A[i] - h); cout << ret << '\n'; }