#include<bits/stdc++.h> 
using namespace std;
const int N=110000;
int n,m,a[N];
bool check(int x)
{
    int s=0, tm=1;
    for(int i=1;i<=n;i++)
    {
        if(a[i]>x)return 0;
        if(a[i]+s<=x)s=s+a[i];
        else
        {
            tm++;if(tm>m)return 0;
            s=a[i];
        } 
    }
    return 1;
}
int main()
{
    scanf("%d%d",&n,&m);
    int R=0, L=0, ans=-1;
    for(int i=1;i<=n;i++)scanf("%d",&a[i]), R=R+a[i]; 
    
    while(L<=R)
    {
        int mid=(L+R)/2;
        if(check(mid)) ans=mid, R=mid-1;
        else                   L=mid+1;
    }
    printf("%d",ans);
    return 0;
}