#include <fstream>
#include <deque>
#define nmax 34570
#define inf 1e18
using namespace std;
ifstream cin("euro.in");
ofstream cout("euro.out");
int n,m,t,x,poz[nmax];
long long v[nmax],dp[nmax],s[nmax],sum;
deque<int>q;
int main()
{
    cin>>n>>t;
    for(int i=1;i<=n;i++){
        cin>>x;
        if(sum<0){
            v[++m]=sum;
            poz[m]=i-1;
            sum=x;
        }else
            sum+=x;
    }
    v[++m]=sum;
    poz[m]=n;
    for(int i=1;i<=m;i++){
        s[i]=v[i]+s[i-1];
        dp[i]=s[i]*poz[i]-t;
        if(i!=1)
            dp[i]=max(dp[i],dp[i-1]+v[i]*poz[i]-t);
        /*for(int j=1;j<=i;j++)
            dp[i]=max(dp[i],dp[j-1]+(s[i]-s[j-1])*poz[i]-t);*/
        while(!q.empty()&&s[q.back()]<=s[i]){
            dp[i]=max(dp[i],dp[q.back()-1]+(s[i]-s[q.back()-1])*poz[i]-t);
            q.pop_back();
        }
        if(!q.empty())
            dp[i]=max(dp[i],dp[q.back()-1]+(s[i]-s[q.back()-1])*poz[i]-t);
        q.push_back(i);
    }
    cout<<dp[m];
    return 0;
}