#include <fstream>
#define NM 34569
using namespace std;
ifstream f("euro.in");
ofstream g("euro.out");
long long n,t,i,j,m;
long long v[NM],s[NM],q[NM],l[NM],dp[NM];
int main()
{
    f>>n>>t; m=1;
    for(i=1;i<=n;++i){
        f>>v[i];
        s[i]=s[i-1]+v[i];
        if(q[m]<0) m++;
        q[m]+=v[i];
        l[m]=i;
    }
    for(i=1;i<=m;++i){
        dp[i]=-(1LL<<60);
        for(j=i;j>=0&&(i-j)*(i-j)<=t+1000;--j)
            dp[i]=max(dp[i],dp[j]+((s[l[i]]-s[l[j]])*l[i]-t));
    }
    g<<dp[m]<<'\n';
    return 0;
}