#include <bits/stdc++.h>
using namespace std;
ifstream in("euro.in");
ofstream out("euro.out");
typedef long long ll;
const ll lim=(5LL<<13);
const ll inf=2e18+7;
ll dp[lim],v[lim],s[lim],q[lim],l[lim];
int main()
{
    ll n,t,i,m,j;
    in>>n>>t;
    for(i=m=1;i<=n;++i)
    {
        in>>v[i];
        s[i]=s[i-1]+v[i];
        m+=(q[m]<0);
        q[m]+=v[i];
        l[m]=i;
    }
    for(i=1;i<=m;++i)
    {
        dp[i]=-inf;
        for(j=i;j>=0 and (i-j)*(i-j)<=t+1000;--j)
            dp[i]=max(dp[i],dp[j]+(s[l[i]]-s[l[j]])*l[i]-t);
    }
    out<<dp[m]<<'\n';
    return 0;
}