#include <iostream>
#include <queue>
#include<vector>
#define int long long
using namespace std;
signed main() {
int n,k;cin>>n>>k;
vector<int>ai(n);
for(int i=0;i<n;i++)cin>>ai[i];
priority_queue<int>max_Heap;
int total_jump=0;
int total_time=0;
for(int i=n-1;i>=0;i--){
total_time+=ai[i];
if((i+1)%k==0 && !max_Heap.empty()){
total_jump+=max_Heap.top();
max_Heap.pop();
}
max_Heap.push(ai[i]); //
}
cout<<total_time-total_jump;
return 0;
}
// 64 位输出请用 printf("%lld")

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