#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const int INF=1e9;

 /* Library:
  https://yukicoder.me/users/24530/ai_code */

int main() {
	cin.tie(nullptr),cout.tie(nullptr);
	ios::sync_with_stdio(false);
  
  ll n,d,p;
  cin >> n >> d >> p;
  
  vector<ll> a(n);
  for(int i=0; i<n; i++){
    cin >> a[i];
  }
  sort(a.rbegin(),a.rend());
  
  ll kai=0;
  for(int i=0; i<n; i+=d){
    ll k=0;
     for(int j=i; j<min(i+d,n); j++){
     k+=a[j];
  }
  kai+=min(k,p);
  }
  
  cout << kai << endl;
}