#include <bits/stdc++.h>
using namespace std;


ifstream fin("transport.in");
ofstream fout("transport.out");

int n, k, v[16005];

int howMany (int cap) {
    int nr_tr = 1, s = 0;
    for (int i = 1; i <= n; i++) {
        if (s + i <= cap) {
            s += v[i];
        }
        else {
            nr_tr++;
            s = v[i];
        }
    }
    return nr_tr;
}


int main()
{
    fin >> n >> k;
    for (int i = 1; i <= n; i++) {
        fin >> v[i];
    }
    int st = 1, dr = 256000000, sol;
    while (st <= dr) {
        int mij = (st + dr) / 2;
        if (howMany(mij) <= k) {
            sol = mij;
            dr = mij - 1;
        }
        else {
            st = mij + 1;
        }
    }
    fout << sol-1;
    return 0;
}