#include <bits/stdc++.h>
using namespace std;
int n, m;
int a[112345];
//看看如果每段和都不超过 maxSum，最少分成的段数是否不超过 M。
bool check(int maxSum)
{
    int cnt = 1;
    int nowSum = 0;
    for (int i = 1; i <= n; i++)
    {
        if (a[i] > maxSum)
            return false;
        if (nowSum + a[i] <= maxSum)
            nowSum += a[i];
        else
        {
            cnt++;
            nowSum = a[i];
        }
    }
    return cnt <= m;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    int l = 0;
    int r = 1000000000;
    int ans = -1;
    while (l <= r)
    {
        int mid = (l + r) / 2;
        if (check(mid))
        {
            ans = mid;
            r = mid - 1; //调整上限，看能不能更小
        }
        else
            l = mid + 1;
    }
    cout << ans << "\n";
    return 0;
}