/* Sample program illustrating input/output */
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int main(void){
//Helpers for input and output
    int N, K;
    cin >> N >> K;
    vector<int> C(N), t(K);
    for(int i = 0; i < N; i++){
        cin >> C[i];
    }
    for(int i = 0; i < K; i++){
        t[i] = 0;
    }
    int result=0, j=0;
    sort(C.begin(), C.end());
    for(int i=N-1; i >= 0; i--) {
        result += (t[j]+1)*C[i];
        t[j]++;
        j = (j+1) % K;
    }
    cout << result << "
";
    
    return 0;
}