// 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<pair<ll,ll>, null_type,less<pair<ll,ll>>, rb_tree_tag,tree_order_statistics_node_update> // using 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());
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++) {
oset t;
for (ll k = 0; k <= min(maxl, h); k++) {
t.insert({dp[i-1][k], k});
}
for (ll j = 0; j <= maxl; j++) {
ll tempmin = t.begin()->first;
dp[i][j] = tempmin + abs(j - s[i]);
ll low = j - h, high = j + h + 1;
if (low >= 0) {
t.erase({dp[i-1][low], low});
}
if (high <= maxl) {
t.insert({dp[i-1][high], high});
}
}
}
ll ans = *min_element(dp[n-1].begin(), dp[n-1].end());
pr(ans);
}
