#include<bits/stdc++.h>

using namespace std;

int main(){

    int n,m,mx=0;

    priority_queue<int> pq;

    cin>>n>>m;

    for(int i=0,buffer;i<n;i++){

        cin>>buffer;

        if((int)pq.size()<m)

            pq.push(-buffer);

        else{

            buffer+=-(pq.top());

            pq.pop();

            pq.push(-buffer);

        }

        mx=max(mx,buffer);

    }

    cout<<mx;

    return 0;

}