#include <fstream>

using namespace std;

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

const int NMAX = 16005;

int v[NMAX], n, m, maxim, s, sol = -1;


int check(int k)
{
    int nr = 1, suma = 0;
    for(int i = 1; i <= n; i++)
    {
        if(suma + v[i] <= k)
        {
            suma += v[i];
        }
        else
        {
            suma = v[i];
            nr++;
        }
    }
    return (nr <= m);
}

void cautbin()
{
    int l = maxim, r = s;
    while(l <= r)
    {
        int mijloc = (l + r) / 2;
        if(check(mijloc))
        {
            sol = mijloc;
            r = mijloc - 1;
        }
        else
        {
            l = mijloc + 1;
        }
    }
}

int main()
{
    fin >> n >> m;
    for(int i = 1; i <= n; i++)
    {
        fin >> v[i];
        maxim = max(maxim, v[i]);
        s += v[i];
    }
    cautbin();
    fout << sol;
}