#include <fstream>
#define NM 16005

using namespace std;

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

int n,k,s,mx,v[NM],sum,i;

int main()
{
    fin >> n >> k;
    for (i=1; i<=n; i++)
      fin >> v[i], s+=v[i];
    s/=k;
    mx=0;
    for (i=1; i<=n; i++)
    {
        sum+=v[i];
        if (sum>=s)
        {
            if (mx<sum)
              mx=sum;
            sum=0;
        }
    }
    if (sum>=s)
    {
        if (mx<sum)
          mx=sum;
        sum=0;
    }
    fout << mx << '\n';
    fin.close();
    fout.close();
    return 0;
}