#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)

int main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	
	int N, M;
	cin >> N >> M;
	
	priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> que;
	rep(i, 0, M) que.push(make_pair(0, i));
	
	rep(i, 0, N) {
		ll T;
		cin >> T;
		
		ll v = que.top().first + T;
		int idx = que.top().second;
		que.pop();
		que.push(make_pair(v, idx));
	}
	
	ll ans = 0;
	while (!que.empty()) {
		ans = max(ans, que.top().first);
		que.pop();
	}
	cout << ans << '\n';
}