#include<stdio.h>
//#include<conio.h>

#define X 16001

int main()
{
 //clrscr();

 freopen("transport.in","r",stdin);
 freopen("transport.out","w",stdout);

 int a[X],n,k,i,saux,sum=0,max=0;

 scanf("%d%d",&n,&k);
 for(i=1; i<=n; ++i)
 {
  scanf("%d",&a[i]);
  sum+=a[i];
 }

 sum/=k;
 for(i=1; i<=n;)
 {
  saux=0;
  while(saux<sum && i<=n) { saux+=a[i]; ++i; }
  if(saux>max) max=saux;
 }

 printf("%d\n",max);

 return 0;
}