#include<fstream>
#include<set>
#include<cassert>

using namespace std;

const char iname[]="euro.in";
const char oname[]="euro.out";
const int maxn=36000;

ifstream f(iname);
ofstream g(oname);

long long a[maxn],s[maxn],maxt,rez,dp[maxn],zi[maxn],ok,x;

int i,n,t;

struct maxv
{
    bool operator()(const int &x,const int &y)
    {
        return dp[x]-s[x]*i<dp[y]-s[y]*i;
    }
};
struct zile
{
    bool operator()(const int &x,const int &y)
    {
        return zi[x]<zi[y];
    }
};
set<int,zile> R;
set<int,maxv> S;

int main()
{
    f>>n>>t;
    for(i=1;i<=n;++i)
        f>>a[i],s[i]=s[i-1]+a[i];
    maxt=rez=0;
    S.insert(0);
    for(i=1;i<=n;++i)
    {
        set<int,maxv>::iterator it,jt;
        x=*(S.rbegin());
        dp[i]=dp[x]+(s[i]-s[x])*i-t;
        it=S.insert(i).first;
        ok=1;

        //Trebuie eliminat :?
        jt=it;
        jt++;
        if(jt!=S.end())
            if(s[*it]>=s[*jt])
            {
                S.erase(it);
                ok=0;
            }
        //daca nu
        if(ok)
        {
            //scaotem ratia
            if(it!=S.begin())
            {
                jt=it;
                jt--;
                R.erase(*jt);
            }
            //scoate alea cu crestere mai mica
            while(it!=S.begin())
            {
                jt=it;
                jt--;
                if(s[*jt]>=s[i])
                    R.erase(*jt),S.erase(jt),it=S.find(i);
                else
                    break;
            }
            //adaugam ratia de crestere inapoi
            if(it!=S.begin())
            {
                jt=it;
                jt--;
                x=dp[*it]-dp[*jt];
                x=x/(s[*it]-s[*jt])+1;
                zi[*jt]=x;
                assert(x>i);
                R.insert(*jt);
            }
            //adaugam ratia de crestere inainte
            jt=it;
            ++it;
            if(it!=S.end())
            {
                x=dp[*it]-dp[*jt];
                x=x/(s[*it]-s[*jt])+1;
                assert(x>i);
                zi[*jt]=x;
                R.insert(*jt);
            }
        }
      //  for(set<int,maxv>::iterator it=S.begin();it!=S.end();++it)
       //     fprintf(stderr,"%d ",*it);
       // printf("\n");
        while(R.size()>0&&zi[*R.begin()]<=i+1)
        {
            x=*R.begin();
            R.erase(x);
            if(zi[x]<=i)
                continue;
            it=S.find(x);
            //eliminam in fata
            while(1)
            {
                jt=it;
                ++jt;
                if(jt!=S.end()&&dp[*it]-s[*it]*(i+1)>=dp[*jt]-s[*jt]*(i+1))
                    R.erase(*jt),S.erase(jt),it=S.find(x);
                else
                    break;
            }
            //adaugam ratia in fata
            jt=it;
            ++it;
            if(it==S.end())
                continue;
            x=dp[*it]-dp[*jt];
            x=x/(s[*it]-s[*jt])+1;
           // assert(x>i);
            zi[*jt]=x;
            R.insert(*jt);
        }
    }
    g<<dp[n]<<"\n";
}