/*input

*/

//__author__= "Ravi Shankar"

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

/*******usful typedef's *********/

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> ii;
typedef list<int>li;
typedef list<li>lii;
typedef set<int>si;
typedef set<si>sii;
typedef map<int,int> mi;

/**************some useful macros/preprocessor********/

#define be_fast std::ios::sync_with_stdio(false);std::cin.tie(NULL)
#define print cout <<
#define ict int t;cin>>t;while(t--)
#define loop(a,b,c)   for (int (a)=(b); (a)<(c); ++(a))
#define loopn(a,b,c)  for (int (a)=(b); (a)<=(c); ++(a))
#define loopd(a,b,c)  for (int (a)=(b); (a)>=(c); --(a))
#define ina(a,n)  loop(i,0,n) cin>>a[i];
#define outa(a,n) loop(i,0,n) cout << a[i]<<" "; cout <<endl;
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define inf INT_MAX
#define linf LONG_MAX
#define MOD 1000000007
#define amount 100005

///iterator range

#define all(c) c.begin(), c.end()
///reverse all iterator
#define rall(c) c.rbegin(),c.rend()
#define tr(c,i) for(typeof((c).begin() i = (c).begin(); i != (c).end(); i++))
#define present(c,x) ((c).find(x) != (c).end())
#define cpresent(c,x) (find(all(c),x) != (c).end())

/***************all user defines functions ******************/


/******************main starts here *************************/

int main() {
    be_fast;
    int n,c,k;
    cin>>n>>k;
    int arr[n];
    ina(arr,n);
    sort(arr,arr+n);
    int i=0;
    ll ans=0;
    while(i<n){
    	ans+=arr[i];
    	i+=k;
    }
    cout << ans <<endl;
}
/*******************main ends here **************************/