#include<bits/stdc++.h>
using namespace std;
ifstream fin("transport.in");
ofstream fout("transport.out");

long long n, v[200005], k, sum[200005];

long long verif(long long poz)
{
    long long curr_sum = 0, ans = 0;
    for (int i = 1; i <= n; i++) {
        if (curr_sum + v[i] <= poz)
            curr_sum += v[i];
        else {
            curr_sum = v[i];
            ans++;
        }
    }

    if (ans >= k)
        return 1;
    return 0;
}

int main()
{
    cin >> n >> k;
    for (long long i = 1; i <= n; i++) {
        cin >> v[i];
        sum[i] = sum[i - 1] + v[i];
    }

    long long st = 1, dr = 1e18, poz = 0;
    while (st <= dr) {
        long long mijl = (st + dr) / 2;
        if (verif(mijl) == 1) {
            st = mijl + 1;
        } else {
            dr = mijl - 1;
            poz = mijl;
        }
    }

    cout << poz;
    return 0;
}