#include <fstream>
using namespace std;
ifstream cin("transport.in");
ofstream cout("transport.out");
long long s,st,dr,mid,poz;
int v[500001],mx,n,k,i;
int verif(long long mid)
{
    s=0;
    int t=1;
    for(i=1; i<=n; i++)
    {
        s+=v[i];
        if(s>mid)
        {
            t++;
            s=v[i];
        }
    }
    if(t<=k) return 1;
    return 0;
}
int main()
{
    cin>>n>>k;
    for(i=1; i<=n; i++)
    {
        cin>>v[i];
        mx=max(v[i],mx);
        s+=v[i];
    }
    st=mx;
    dr=s;
    while(st<=dr)
    {
        mid=(st+dr)/2;
        if(verif(mid))
        {
            poz=mid;
            dr=mid-1;
        }
        else st=mid+1;
    }
    cout<<poz;
    return 0;
}