#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5 + 5;
ll a[N], suff[N];

int main() {
	int n, d;
	ll p;
	cin >> n >> d >> p;
	for(int i=1;i<=n;++i)
		cin>>a[i];
	sort(a + 1, a + n + 1, greater < ll>());
	for (int i = n; i >= 1; i--) {
		suff[i] = suff[i + 1] + a[i];
	}
	ll ans = suff[1];
	for (ll k = 1; k <= (n + d - 1) / d + 1; k++) {
		ll c = k * d;
		ll cost = k * p; 
		if (c < n) {
			cost += suff[c + 1];
		}
		ans = min(ans, cost);
	}
	cout << ans << endl;

	return 0;
}