#include <cstdio>
#define FIN "transport.in","r",stdin
#define FOUT "transport.out","w",stdout

using namespace std;

int n,k,a[16005],st,dr,mid,i,sol,nr;

int check(int max_capacity,int capacity, int vf)
{
    if(!vf)return 1;
    if(a[vf]>max_capacity)return 100+check(max_capacity,capacity,0);
    if(capacity+a[vf]<=max_capacity) return check(max_capacity,capacity+a[vf],vf-1);
    return 1+check(max_capacity,0,vf);
}

int main()
{
    freopen(FIN);
    freopen(FOUT);

    scanf("%d %d",&n,&k);

    for(i=1;i<=n;i++)
        scanf("%d",&a[i]),dr+=a[i];

    st=1;
    sol=-1;
    while(st<=dr)
    {
        mid=(st+dr)/2;
        nr=check(mid,0,n);

        if(nr==k)sol=mid,dr=mid-1;
        else if(nr<k && sol==-1)dr=mid-1;
        else if(nr>k) st=mid+1;
        else st=dr+1;
    }

    printf("%d",sol);

    return 0;
}