#include <iostream>
#include <fstream>
using namespace std;
int a[16001];
int main()
{
    int n,k,mx=0,s=0,tr=0,sum=0,lim,i,nr,maxi=0;
    ifstream cin("transport.in");
    ofstream cout("transport.out");
    cin>>n>>k;
    for(i=1;i<=n;i++)
    {
        cin>>a[i];
        s=s+a[i];
        if(a[i]>mx)
            mx=a[i];
    }
    nr=s/k;
    if(nr>mx)
        lim=nr;
    else lim=mx;
    i=1;
    while(tr<=k)
    {
        sum=0;
        while(i<=n &&sum<lim)
        {
            sum=a[i]+sum;
            i++;
        }
        if(sum>maxi)
            maxi=sum;
        tr++;
       // cout<<sum<<'\n';
    }
    cout<<maxi;
    return 0;
}