#include <fstream>
using namespace std;

ifstream in;
ofstream out;

int sal[16002];

int main(int argc, char *argv[])
{
    in.open("transport.in");
    out.open("transport.out");
    int n, k, max = 0;
    in >> n >> k;
    for (int i = 1; i <= n; i++) {
        in >> sal[i];
        if (sal[i] > max)
            max = sal[i];
    }

    int count = 0, sum;

    int i;
    for (i = max; i <= 16000; i++) {
        for (int j = 1; j <= n; j++) {
            if (sum >= i)
                count++;
            else
                sum += j;
        }
        if (count <= k)
            break;
    }

    out << i + 1 << endl;

    in.close();
    out.close();
    return 0;
}