#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 last_poz = 0, ans = 0;
    for (long long i = 1; i <= n; i++)
        if (v[i] > poz)
            return 0;
    for (long long i = 1; i <= n; i++) {
        if (sum[i] - sum[last_poz] > poz) {
            ans++;
            last_poz = i - 1;
        }
    }

    if (last_poz != n - 1)
        ans++;
    if (ans > k)
        return 1;
    return 0;
}

int main()
{
    fin >> n >> k;
    for (long long i = 1; i <= n; i++) {
        fin >> 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;
        }
    }

    fout << poz;
    return 0;
}