/* -*- coding: utf-8 -*-
 *
 * 3471.cc:  No.3471 繧ｸ繝｣繝・ず繧ｵ繝ｼ繝舌・縺ｮ雋闕ｷ蛻・淵 - yukicoder
 */

#include<cstdio>
#include<queue>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 200000;
/* typedef */

using ll = long long;

/* global variables */

int ts[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; i++) scanf("%d", ts + i);

  priority_queue<ll> q;
  for (int i = 0; i < m; i++) q.push(0);

  for (int i = 0; i < n; i++) {
    auto qt = q.top(); q.pop();
    q.push(qt - ts[i]);
  }

  ll maxt = 0;
  while (! q.empty()) maxt = -q.top(), q.pop();

  printf("%lld\n", maxt);
  
  return 0;
}