#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define endl '\n'
#define int ll
const int N = 1e5 + 10;
int n, m, a[N], l = 0, r = 1e10+10, prefix[N];
bool check(int ans)
{
	int cnt = 0;
	int j = 1;
	for (int i = 1; i <= n; i++)
	{
		if (a[i] > ans) {
			j++; 
			cnt++;continue;
		}
		while (prefix[i] - prefix[j-1] <= ans&&i<=n) i++;
		cnt++;
		j = i;
		if (j == n) cnt++;
	}
	if (cnt > m) return false;
	return true;
}
signed main()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i]; prefix[i] = prefix[i - 1] + a[i];
	}
	while (l + 1 != r)
	{
		int mid = l + (r - l) / 2;
		if (check(mid)) r = mid;
		else l = mid;
	}
	cout << r;
	return 0;
}