//  Array Division

#include<bits/stdc++.h>

using namespace std;
using ll = long long;

bool check_sum(vector<ll> &a, ll target_sum, int max_number_of_sub_arrays) {
    ll sum = 0;
    ll count = 1;
    for (int i{}; i < a.size(); i++) {
        if (sum + a[i] <= target_sum) {
            sum += a[i];
        } else {
            sum = a[i];
            if (sum > target_sum) return false;
            count++;
        }
    }
    return count <= max_number_of_sub_arrays;
}

int main() {
    int n, k; cin >> n >> k;
    vector<ll> a(n);
    ll sum = 0;
    for (int i{}; i < n; i++) {
        cin >> a[i];
        sum += a[i];
    }
    ll lo = 0;
    ll hi = INT64_MAX / 3;
    while (lo < hi) {
        ll mid = (lo + hi) / 2;
        if (check_sum(a, mid, k)) {
            hi = mid;
        } else {
            lo = mid + 1;
        }
    }
    cout << lo << endl;
}