#include<iostream>
#include<algorithm>
#include<functional>
using namespace std;
int main()
{
int n,k;
cin>>n>>k;
int ar[n];
for(int i=0;i<n;i++)
cin>>ar[i];
sort(ar, ar+n,greater<int>());
int q,money=0;
for(int it=0;it<n;++it)
{
q=(it)/k;
money+=(q+1)*ar[it];
}
cout<<money<<endl;
return 0;
}
#include<algorithm>
#include<functional>
using namespace std;
int main()
{
int n,k;
cin>>n>>k;
int ar[n];
for(int i=0;i<n;i++)
cin>>ar[i];
sort(ar, ar+n,greater<int>());
int q,money=0;
for(int it=0;it<n;++it)
{
q=(it)/k;
money+=(q+1)*ar[it];
}
cout<<money<<endl;
return 0;
}