#为社么二分端点不能取0和1e9,过不了第四个点

#include <cstring>
#include <algorithm>
#include <iostream>
#include <map>
using namespace std;
const int N = 1e5 + 10;
typedef unsigned long long LL;
typedef pair<int, int> PII;
int a[N];
int n, m;

bool check(int mid)
{
    LL num = 0, cnt = 1;

    for (int i = 0; i < n; i++)
    {
        num += a[i];
        if (num > mid)
        {
            num = a[i];
            cnt++;
        }
    }

    return cnt <= m;
}

int main()
{
    cin >> n >> m;
    int l, r;
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
    }
     l = 0, r = 1e9;

    while (l < r)
    {
        int mid = l + r >> 1;
        if (check(mid))
            r = mid;
        else
            l = mid + 1;
    }

    cout << r << endl;

    return 0;
}