import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[] t = new int[n];
		for (int i = 0; i < n; i++) {
			t[i] = sc.nextInt();
		}
		sc.close();

		PriorityQueue<Obj> que = new PriorityQueue<>((o1, o2) -> {
			if (o1.v != o2.v) {
				return Long.compare(o1.v, o2.v);
			}
			return o1.i - o2.i;
		});
		for (int i = 0; i < m; i++) {
			Obj o = new Obj();
			o.i = i;
			que.add(o);
		}

		long ans = 0;
		for (int i = 0; i < n; i++) {
			Obj o = que.poll();
			o.v += t[i];
			que.add(o);
			ans = Math.max(ans, o.v);
		}
		System.out.println(ans);
	}

	static class Obj {
		int i;
		long v;
	}
}