#include<stdio.h>
int main(){
    int s,max,n,k,saux,tr,l1,l2,v[16001],m,i;
    freopen("transport.in","r",stdin);
    freopen("transport.out","w",stdout);
    scanf("%d%d",&n,&k);
    s=0;
    max=0;
    for(i=1;i<=n;i++){
        scanf("%d",&v[i]);
        s+=v[i];
        if(v[i]>max)
            max=v[i];
    }
    l1=max;
    l2=s;
    tr=0;
    while(tr!=k){
        m=(l1+l2)/2;
        saux=0;tr=0;
        for(i=1;i<=n;i++)
            if(saux+v[i]<=m)
                saux+=v[i];
            else{
                tr++;
                saux=0;
            }
        if(tr<k)
            l2=m/2;
    }
    printf("%d",m*2);
    return 0;
}