#include <cstdio>
#include <algorithm>
using namespace std;

int n, t, x, sum[34570];
long long d[34570];
int main()
{
    freopen("euro.in", "r", stdin);
    freopen("euro.out", "w", stdout);
    scanf("%d%d", &n, &t);
    for(int i = 1; i <= n ; ++i){
        scanf("%d", &x);
        sum[i] = sum[i - 1] + x;
        d[i] = 1LL * sum[i] * i - t;
        for(int j = 1; j < i ; ++j)
            d[i] = max(d[i], d[j] + 1LL * (sum[i] - sum[j]) * i - t);
    }
    printf("%d", d[n]);
    return 0;
}