#include<stdio.h>
#define N 16001
int n,v[N],max;
void suma (int m)
{
	int s=0;
	for (int i=1; i<=n; ++i)
	{
		s+=v[i];
		if (s>m)
		{
			int s1=m-(s-v[i]),s2=s-m;
			if (s1>s2){
				if (max<s)
				max=s;}
			else
			{
				if (max<s)
				max=s;
				--i;
			}
			s=0;
		}
	}
	printf("%d\n",max);
}
void citire()
{
	freopen("transport.in","r",stdin);
	freopen("transport.out","w",stdout);
	int m;
	scanf("%d%d",&n,&m);
	int s=0;
	for (int i=1; i<=n; ++i)
	{
		scanf("%d",&v[i]);
		s+=v[i];
	}
	int med=s/m;
	suma(med);
}
int main()
{
	citire();
	return 0;
}