C

#include <bits/stdc++.h>
using namespace std;

#define ll     long long

int main()
{
    ll int n, d, p;
    cin>>n>>d>>p;

    vector<ll int> f(n);
    for(auto &e: f)     cin>>e;

    multiset<ll int> mst;
    for(auto e: f)      mst.insert(e);

    ll int val = accumulate(f.begin(), f.end(), 0ll);

    ll int ans = val;

    ll int b = 0;

    while(b < n)
    {
        b += d;
        val += p;

        for(int i=0; i<d && mst.size()>0; i++)
        {
            val -= *mst.rbegin();
            mst.erase(--mst.end());
        }

        ans = min(ans, val);
    }

    cout<<ans<<"\n";
}