#include <iostream>
#include <bits/stdc++.h>
using ll = long long;
using namespace std;

int main()
{
    ll n, k; cin >> n >> k;
    vector<ll> v(n);
    for (ll i = 0; i < n; i++){
        cin >> v[i];
    }
    sort(v.begin(), v.end());
    reverse(v.begin(), v.end());
    ll ans = 0, remain = n;
    for (ll i = n-1; i >= 0; i--){
        ans += v[i];
        for (ll j = 0; j < min(k, remain); j++){
            v[j] += v[i];
        }
        remain--;
    }
    cout << ans;
    return 0;
}