#include <bits/stdc++.h>
#define endl '\n'
#define int long long 
using namespace std;

void solve(){
    int N, M;
    cin >> N >> M;
    vector<int> arr(N), pref(N + 1), suff(N + 1), sum(N + 1);
    for(int i = 0; i < N; i ++){
        cin >> arr[i];
    }
    sort(arr.begin(), arr.end());
    for(int i = 0; i < N; i ++){
        pref[i + 1] = pref[i] + M + 1 - (i == 0 ? 0 : arr[i - 1]);
        suff[N - i - 1] = suff[N - i] + (i == 0 ? M + 1 : arr[N - i]);
    }
    int ans = 0;
    for(int i = 0; i < N; i ++){
        int s = suff[i];
        int p = pref[i];
        ans = max({ans, s + p - ((M + 1) * i) + i * arr[i], p + s - (N - i) * (i > 0 ? arr[i - 1] : 0)});
    }
    cout << ans << endl;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    solve();
    return 0;
}