#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define pf push_front
#define ll long long
#define ull unsigned long long
#define pi pair<int,int>
#define pl pair<ll,ll>
#define vll vector<long,long>
#define EPSILON 0.000001

using namespace std;

ifstream fin("GCDP.in");
ofstream fout("GCDP.out");

const ll NMAX = 1e5+5, INF = 1e18, MOD = 666013 , MMAX = 1e2 + 5, inf = INT_MAX;


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

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

Line segm_tree[4 * NMAX];

void insert_line(int node, int l, int r, Line ins) {
    if(l == r) {
        if(ins.eval(l) > segm_tree[node].eval(l)) {
            segm_tree[node] = ins;
        }
        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++) {
        cin >> sp[i];
        sp[i] += sp[i - 1];
    }

    insert_line(1, 1, N, {0, 0});

    for(int i = 1; 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;
}