#include<cmath>  
#include<iostream>  
#include<cstdio>
#include<cstring>
 
using namespace std;

const int maxn=2510;
int n,m;
int f[maxn];
int a[maxn];  

int main()
{
	freopen("cowriver.in","r",stdin);
	freopen("cowriver.out","w",stdout);
	scanf("%d%d",&n,&m);  
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&a[i]);  
		a[i]+=a[i-1]; 
	}
	memset(f,63,sizeof(f));  
	f[0]=0;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=i;j++)
		{
			f[i]=min(f[i],f[i-j]+a[j]+2*m);
		}  
	}
	printf("%d\n",f[n]-m);  
	return 0;
}