// Source: https://usaco.guide/general/io
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define eb emplace_back // faster than push_back xD
// pbds UwU
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define oset tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update> // use pair for ms
// my io library :D
#define m1(x) template<class T, class... U> void x(T&& a, U&&... b)
#define m2(x) (ll[]){(x forward<U>(b),0)...}
m1(pr){cout << forward<T>(a); m2(cout << " " <<); cout << "\n";}
m1(re){cin >> forward<T>(a); m2(cin >>);}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
ll n, h; re(n, h);
vector<ll> s(n);
for (ll i{}; i < n; i++) re(s[i]);
ll maxl = *max_element(s.begin(), s.end()) + n*h;
vector<vector<ll>> dp(n, vector<ll>(maxl+1, 1e18));
for (ll i{}; i <= maxl; i++){
dp[0][i] = abs(s[0]-i);
}
for (ll i = 1; i < n; i++){
for (ll j{}; j < maxl; j++){
for (ll pj = max(0LL, j - h); pj <= min(maxl - 1, j + h); pj++) {
dp[i][j] = min(dp[i][j], dp[i-1][pj]);
}
dp[i][j] += abs(j - s[i]);
}
}
ll ans = 1e18;
for (ll i{}; i < maxl; i++) ans = min(ans, dp[n-1][i]);
pr(ans);
}
