#include<bits/stdc++.h>
using namespace std;
const string hhh="老马666";
const int maxn=2600001;
const int INF=0x7fffffff;
int a[2501],dp[maxn];
int n,m;
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];
	}
	fill(dp+1,dp+n+1,INF);
	for(int i=1;i<=n;i++)
	for(int j=i;j<=n;j++)
	dp[j]=min(dp[j],dp[j-i]+a[i]+2*m);
	printf("%d\n",dp[n]-m);
	return 0;
}