import java.util.*;
import java.lang.*;
import java.io.*;
public class Main
{
        public static long minimumPossibleNumber(long arr[],int n,long m){
                long min=Integer.MIN_VALUE;
                long max=0L;
                for(int i=0;i<n;i++){
                        if(arr[i]>min){
                                min=arr[i];
                        }
                        max+=arr[i];
                }
                Long low=0L;
                long high=max;
                long res=-1L;
                while(low<=high){
                        long mid=low+(high-low)/2;
                        if(isPossible(arr ,n,m,mid)){
                                res=mid;
                                high=mid-1L;
                        }
                        else{
                                low=mid+1L;
                        }
                }
                return res;
        }
        public static boolean isPossible(long arr[] ,int n ,long  m,long mid ){
                long studentCount=1L;
                long pageCount=0L;
                for(int i=0;i<n;i++){
                        if(pageCount+arr[i]<=mid){
                                pageCount+=arr[i];
                        }
                        else{
                                studentCount++;
                                if(studentCount>m||arr[i]>mid){
                                        return false;
                                }
                                pageCount=arr[i];
                        }
                }
                return true;
        }
	public static void main (String[] args) throws java.lang.Exception
	{
		//your code here
                Scanner sc=new Scanner(System.in);
                int n=sc.nextInt();
                long arr[]=new long [n];
                for(int i=0;i<n;i++){
                        arr[i]=sc .nextLong();
                }
                long m=sc.nextLong();
                long ans=minimumPossibleNumber(arr,n,m);
                System.out.print(ans);
	}
}