#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<math.h>
#include<stack>
#include<queue>
#include<iomanip>
#include<bits/stdc++.h>
using namespace std;
#define ull unsigned long long int
#define int unsigned long long
#define double long double
int f[200050];
int n,d,p;
signed main()
{
	std::ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin>>n>>d>>p;
    for(int i=1;i<=n;i++) cin>>f[i];
    sort(f+1,f+n+1);
    //for(int i=1;i<=n;i++) cout<<f[i]<<' ';
    //cout<<"\n";
    int ans=0,lst=n;
    int an=0;
	int i;
	if(d!=1){
	    for(i=n;i>=1;i--){
	    	if(i==lst-d){
	    		if(an>p){
	    			ans+=p;
	    			lst=lst-d;
	    			//cout<<lst<<' '<<an<<' '<<ans<<"\n";
					an=0;
				}
				else break;
			}
			an+=f[i];
		}
		//cout<<lst<<' '<<i<<' '<<p<<"\n";
		an=0;
		for(i=lst;i>=1;i--) an+=f[i];
		ans+=min(an,p);
	}
	else{
		for(i=n;i>=1;i--) ans+=min(p,f[i]);
	}
	cout<<ans;
	return 0;
}
/*
8 3 3
1 1 4 4 5 6 7 8 
*/

WA了14个点,求hack