#include <bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define IDB if (debug)

typedef long long ll;
typedef double ld;
typedef pair <int, int> pii;
const int SZ = 3e5 + 4;
const int oo = 1e9 + 4;
const int mod = 1e9 + 7;
const bool debug = 0;

string s;
ll n, x, t, pr, sum, mn, mx, ok, ans, ind1;
ll a[SZ], p[SZ], l[SZ];
ll indmn, indmn2;

void read() {
    cin >> n >> x;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
}

void solve() {
    if (x >= 0) {
        for (int i = 1; i <= n; i++) {
            sum += a[i];
            if (sum < pr) pr = sum;
            ok = max(ok, sum - pr);
        }
        cout << max(ok, ok * x);
        return;
    }

    for (int i = 1; i <= n; i++)
        p[i] = p[i - 1] + a[i];

    for (int i = n; i > 0; i--)
        l[i] = l[i + 1] + a[i];

    pr = 0;
    for (int i = 1; i <= n; i++) {
        pr = min(pr, p[i]);
        p[i] = p[i] - pr;

//        cout << p[i] << ' ';
    }
//cout << endl;

    pr = 0;
    for (int i = n; i > 0; i--) {
        pr = min(pr, l[i]);
        l[i] = l[i] - pr;
//        cout << l[i] << ' ';

    }
//cout << endl;

    pr = 0;
    ans = 0;
    sum = 0;
    for (int i = 1; i <= n; i++) {
        sum += a[i];

        if (sum > pr) {
            pr = sum;
            ind1 = i;
        }

        ll ns = (sum - pr) * x + l[i + 1] + p[ind1];
        if (ind1 == i) ns = l[i + 1] + p[ind1];
//        cout << ns << ' ' << sum << ' ' << pr << ' ' << ind1 << ' ' << i <<' ' << p[ind1]  << ' ' << l[i + 1] << endl;
        ans = max(ans, ns);
    }

    cout << max(ans, p[n]);
}

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(NULL);

    read();
    solve();
}