//
// Created by Mihai145 on 11/19/2021.
//

#include <fstream>

using namespace std;

ifstream cin("euro.in");
ofstream cout("euro.out");

const int NMAX = 35000;

int N, T;
long long sp[NMAX + 2], dp[NMAX + 2];

struct Line {
    long long m, n;
    long long eval(int x) {
        return m * x + n;
    }
};

Line segm_tree[4 * NMAX];

void insert_line(int node, int l, int r, Line ins) {
    if(l == r) {
        return;
    }

    int mid = (l + r) >> 1;

    bool better_left = ins.eval(l) > segm_tree[node].eval(l),
        better_mid = ins.eval(mid) > segm_tree[node].eval(mid);

    if(better_mid) {
        swap(segm_tree[node], ins);
    }

    if(better_left != better_mid) {
        insert_line(node << 1, l, mid, ins);
    } else {
        insert_line((node << 1) + 1, mid + 1, r, ins);
    }
}

long long query(int node, int l, int r, int x) {
    if(l == r) {
        return segm_tree[node].eval(x);
    }

    int mid = (l + r) >> 1;
    long long candidate = 0;

    if(x <= mid) {
        candidate = query(node << 1, l, mid, x);
    } else {
        candidate = query((node << 1) + 1, mid + 1, r, x);
    }

    return max(segm_tree[node].eval(x), candidate);
}

int main() {
    cin >> N >> T;

    for(int i = 1; i <= N; i++) {
        int x; cin >> x;
        sp[i] = sp[i - 1] + x;
    }

    dp[1] = sp[1] * 1 - T;
    insert_line(1, 1, N, {-sp[1], dp[1]});

    for(int i = 2; i <= N; i++) {
        dp[i] = sp[i] * i - T + query(1, 1, N, i);
        insert_line(1, 1, N, {-sp[i], dp[i]});
    }

    cout << dp[N] << '\n';
    return 0;
}