#include<stdio.h>

int N;
int A[16001];
int sum;
int K;
int MAX;
int MAX2;
int nr;

int solve(int sum)
{
	MAX = 0;
	int nr = 1;
	int a = 0;
	for(int i=1;i<=N;i++)
	{
		if(a + A[i]<=sum)
			a += A[i];
		else
			a = A[i],nr ++;
		if(MAX<a)
			MAX = a;
	}
	return nr;
}

int main()
{
	FILE *f = fopen("transport.in","r");
	FILE *g = fopen("transport.out","w");
	
	fscanf(f,"%d %d",&N,&K);
	for(int i=1;i<=N;i++)
	{
		fscanf(f,"%d ",&A[i]);
		sum += A[i];
		if(A[i]>MAX)
			MAX = A[i];
	}
	sum /= K;
	sum ++;
	if(sum<MAX)
		sum = MAX;
	nr = solve(sum);
	while(nr != K)
	{
		if(nr < K)
			sum = sum/4*3;
		else
			sum *= 2;
		nr = solve(sum);
	}
	MAX2 = MAX;
	int max = MAX;
	fprintf(g,"%d",MAX2);
	
	fclose(g);
	fclose(f);
	return 0;
}