#include<iostream>
#include<iomanip>
#include<algorithm>
#include<stdio.h>
using namespace std;

int n, m, b[105], a[10005];

int main()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++)
	{
		cin >> a[i];
	}
	int k = 1;
	for (int i = 1; i <= m; i++)b[i] = a[i];
	sort(b + 1, b + 1 + m);
	int l = m+1;
	while (l <= n)
	{
		if (b[k] <= b[k + 1])
		{
			b[k] += a[l];
			l++;
		}
		else
		{
			sort(b + 1, b + 1 + m);
		}
	}
	sort(b + 1, b + 1 + m);
	cout << b[m];
	return 0;
}