#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

ll N, A, B, X, Y;
vector<ll> H;

bool f(ll k = 0) {
  priority_queue <ll> pque;

  for (int i = 0; i < N; ++i) {
    pque.push(max(0LL, H[i] - k));
  }

  for (int i = 0; i < A; ++i) {
    ll h = pque.top();
    pque.pop();
    pque.push(h - X);
  }

  ll sum = 0;
  while (not pque.empty()) {
    ll h = pque.top();
    pque.pop();
    sum += max(0LL, h);
  }

  return (sum <= B * Y);
}

int main() {
  cin >> N >> A >> B >> X >> Y;
  H.resize(N);

  for (int i = 0; i < N; ++i) {
    cin >> H[i];
  }

  if (f()) {
    cout << 0 << endl;
    return 0;
  }

  ll ng = 0;
  ll ok = LLONG_MAX;
  while (abs(ok - ng) >= 2) {
    ll k = (ok + ng) / 2;

    if (f(k)) {
      ok = k;
    } else {
      ng = k;
    }
  }

  cout << ok << endl;

  return 0;
}