#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
#define dbg(x) cerr << #x << " " << x << "\n"
#define pb push_back

const int N = 1e5, INF = 2e9;

int dp[1 + N];
int sum[1 + N];
int a[1 + N];
struct Point {
    int x;
    int y;
};
Point seg[1 + 4 * N];

void upd (int node, int l, int r, int x, int y) {
    if (l == r) {
        if (seg[node].x * l + seg[node].y < x * l + y) {
            swap (seg[node].x, x);
            swap (seg[node].y, y);
        }
        return;
    }
    int mid = (l + r) / 2;
    bool ok1 = (seg[node].x * mid + seg[node].y < x * mid + y);
    bool ok2 = (seg[node].x * r + seg[node].y < x * r + y);
    if (ok1 && ok2) {
        swap (seg[node].x, x);
        swap (seg[node].y, y);
        upd (node * 2, l, mid, x, y);
    }
    if (ok1 && !ok2) {
        upd (node * 2 + 1, mid + 1, r, x, y);
    }
    if (!ok1 && !ok2) {
        upd (node * 2, l, mid, x, y);
    }
    if (!ok1 && ok2) {
        swap (seg[node].x, x);
        swap (seg[node].y, y);
        upd (node * 2 + 1, mid + 1, r, x, y);
    }

}

int qry (int node, int l, int r, int a) {
    if (l == r)
        return seg[node].x * a + seg[node].y;
    int mid = (l + r) / 2;
    if (a <= mid)
        return max (qry (node * 2, l, mid, a), seg[node].x * a + seg[node].y);
    else
        return max (qry (node * 2 + 1, mid + 1, r, a), seg[node].x * a + seg[node].y);
}

int main () {
    freopen ("euro.in", "r", stdin);
    freopen ("euro.out", "w", stdout);

    ios::sync_with_stdio (false);
    cin.tie (0); cout.tie (0);

    int n, t;
    cin >> n >> t;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        sum[i] = sum[i - 1] + a[i];
    }

    for (int i = 1; i <= n; i++)
        dp[i] = -INF;
    dp[0] = 0;
    upd (1, 1, n, -sum[0], dp[0]);
    for (int i = 1; i <= n; i++) {
        dp[i] = qry (1, 1, n, i) - t + sum[i] * i;
        upd (1, 1, n, -sum[i], dp[i]);
    }

    cout << dp[n] << "\n";
    return 0;
}