#include <bits/stdc++.h>

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

int n, k, a[500100];
long long S = 0;
int Verif(long long s)
{
    int i, nr = 1;
    long long sum = 0;
    for(i = 1;i <= n;i++)
    {
        if(s < a[i])
            return 0;
        if(sum + a[i] <= s)
            sum += a[i];
        else
        {
            nr++;
            sum = a[i];
        }
    }
    return(nr <= k);
}
void Cautbin()
{
    long long st = 1, dr = S, mij, s = 1;
    while(st <= dr)
    {
        mij = (st + dr) / 2;
        if(Verif(mij))
        {
            s = mij;
            dr = mij - 1;
        }
        else
            st = mij + 1;
    }
    fout << s;
}

int main()
{
    int i;
    fin >> n >> k;
    for(i = 1;i <= n;i++)
    {
        fin >> a[i];
        S += a[i];
    }
    Cautbin();

    return 0;
}