#include <fstream>
#define nmax 34570
using namespace std;
ifstream cin("euro.in");
ofstream cout("euro.out");
int n,poz[nmax],t,x;
long long dp[nmax],val[nmax];
int main()
{
    cin>>n>>t>>val[1];
    dp[1]=val[1]-t;
    for(int i=2;i<=n;i++){
        cin>>x;
        val[i]=val[i-1];
        poz[i]=poz[i-1];
        if(val[i]<=0){
            val[i]=x;
            poz[i]=i-1;
        }else
            val[i]+=x;
        dp[i]=max(dp[i-1]+1ll*x*i-t,dp[poz[i]]+1ll*val[i]*i-t);
    }
    cout<<dp[n];
    return 0;
}