#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
#include <fstream>
using namespace std;
long long n, a, b, x, y, z = 0;
long long h[100010];
priority_queue<long long> que;
bool solve(long long k) {
	for (int i = 0; i < n; i++) {
		que.push(max(z, h[i] - k));
	}
	for (int i = 0; i < a; i++) {
		long long now = que.top();
		que.pop();
		que.push(max(z, now - x));
	}
	long long ans = 0;
	for (int i = 0; i < n; i++) {
		ans += que.top();
		que.pop();
	}
	if (ans <= b * y) {
		return true;
	}
	else {
		return false;
	}
}
int main() {
	cin >> n >> a >> b >> x >> y;
	for (int i = 0; i < n; i++) {
		cin >> h[i];
	}
	long long l = -1, r = 1000000007;
	while (r - l > 1) {
		long long mid = (l + r) / 2;
		if (solve(mid)) {
			r = mid;
		}
		else {
			l = mid;
		}
	}
	cout << r << endl;
}