#include <fstream>
using namespace std;
ifstream f ("transport.in");
ofstream g ("transport.out");
int i,j,k,l,n,v[2000000],maxi;
int check(int x)
{
    int i,j=1,s=x;
    for (i=1;i<=n;)
        if (s>=v[i])
            s-=v[i],++i;
        else if (s<v[i]&&s==x)
            return 1000000000;
        else ++j,s=x;

    return j;
}
int main()
{
    f>>n>>k;
    for (i = 1; i <= n + 1 ; ++i )
        {f >> v[i];
        if (v[i-1]>maxi)
            maxi=v[i-1];}
    int st=1,dr=100000000;
    while(st<dr)
        {   int mij=(st+dr)/2;
            int t=check(mij);
            if (t>k)
                st=mij+1;
            else dr=mij-1;
        }
    g<<st;

    return 0;
}