#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int n;
  int a, b;
  int pizza;
  double ans = 0;
  int top[300];
  cin >> n;
  cin >> a >> b >> pizza;
  for (int i = 0; i < n; i++) {
    cin >> top[i];
  }
  sort(top, top + n, greater<int>());
  ans = pizza / a;
  for (int i = 0; i < n; i++) {
    a += b;
    pizza += top[i];
    ans = max(ans, (double)pizza / a);
  }
  cout << ans << endl;
  return 0;
}
