#include<bits/stdc++.h>

using namespace std;

#define ll long long

ll n, k, x;
vector<ll> v;


int main(){
  cin >> n >> k;
  for(int i = 0; i < n;i++){
    cin >> x;
    v.push_back(x);
  }
  sort(v.begin(), v.end());

  ll prefix[n+5];
  prefix[0] = 0;
  for(ll i = 1; i < n;i++){
    prefix[i] = prefix[i-1] + v[i] - v[i-1];
    //cout << prefix[i] << " ";
  }
  //cout << endl;

  ll mn = 1000000000000000;
  ll sum = -n;
  sum *= (n-1);
  sum /= 2;
  sum *= k;

  //cout << sum << endl;
  for(ll i = 0; i < n;i++){
    sum += prefix[i];
  }
  //cout << sum << endl;
  mn = min(mn, sum);
  for(ll i = 1; i < n;i++){
    sum += (i*(v[i] - v[i-1] - k));
    //cout << sum << " sum1" << endl;
    sum -= (v[i] - v[i-1] - k)*(n-i);
    //cout << sum << " sum2" << endl;
    mn = min(mn, sum);
  }

  cout << abs(mn) << endl;
}