#include<bits/stdc++.h>
using namespace std;
int a[11100];
int main()
{
    int n, m;scanf("%d%d", &n, &m);
    for(int i=1;i<=n;i++)scanf("%d", &a[i]);
    priority_queue<int, vector<int>, greater<int>>Q;//小根堆
  
    int ans=0;
    for(int i=1;i<=n;i++)
    {
        if(Q.size()<m)
        {
            Q.push(a[i]);ans=max(ans, a[i]);
        }
        else
        {
            int x=Q.top()+a[i];Q.pop();
            Q.push(x);ans=max(ans, x);
            
        }
    }
    printf("%d\n", ans);
    return 0;
}