#include <bits/stdc++.h>
using namespace std;
#define MOD1 1000000007
#define MOD2 998244353
#define fir first
#define sec second
#define pushf push_front
#define pushb push_back
#define popf pop_front
#define popb pop_back
#define mp make_pair
#define all(a) a.begin(), a.end()
#define lbound(v, x) lower_bound(all(v), x) - v.begin()
#define ubound(v, x) upper_bound(all(v), x) - v.begin()
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
#define FOR1(a) for (int _ = 0; _ < (a); ++_)
#define FOR2(i, a) for (int i = 0; i < (a); ++i)
#define FOR3(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR1(a) for (int _ = (a)-1; _ >= 0; --_)
#define RFOR2(i, a) for (int i = (a)-1; i >= 0; --i)
#define RFOR3(i, a, b) for (int i = (b)-1; i >= (a); --i)
#define overload3(a, b, c, d, ...) d
// Always choose the fourth argument to call. Hence, which function to call is determined by the number of given arguments.
#define REP(...) overload3(__VA_ARGS__, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define RREP(...) overload3(__VA_ARGS__, RFOR3, RFOR2, RFOR1)(__VA_ARGS__)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<char> vc;
typedef vector<string> vs;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef vector<vb> vvb;
typedef vector<vc> vvc;
typedef vector<vpii> vvpii;
typedef vector<vpll> vvpll;
typedef queue<int> qi;
typedef queue<ll> qll;
typedef queue<pii> qpii;
typedef queue<pll> qpll;
typedef deque<int> dqi;
typedef deque<ll> dqll;
typedef deque<pii> dqpii;
typedef deque<pll> dqpll;
typedef priority_queue<int> pqi;
typedef priority_queue<ll> pqll;
typedef priority_queue<pii> pqpii;
typedef priority_queue<pll> pqpll;
typedef priority_queue<int, vi, greater<int> > r_pqi;
typedef priority_queue<ll, vll, greater<ll> > r_pqll;
typedef priority_queue<pii, vpii, greater<pii> > r_pqpii;
typedef priority_queue<pll, vpll, greater<pll> > r_pqpll;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll n, h;
cin >> n >> h;
ll l = 0, r = 0, pos = 0;
// L and R are the left and right half of the slope (decreasing and increasing gradient)
pqll L, R;
ll ans = 0;
for (int i = 1; i <= n; ++i) {
ll a; cin >> a;
if (a >= pos) {
R.push(-a+r);
R.push(-a+r);
// rebalances R
L.push(-R.top()+r-l);
R.pop();
ans += a-L.top()-l;
}
else {
L.push(a-l);
L.push(a-l);
// rebalances L
R.push(-L.top()-l+r);
L.pop();
ans += -R.top()+r-a;
}
// f'(x) = f(y) for abs(x-y) < h is as good as expanding the left and right half of the slope by h.
l -= h;
r += h;
pos = L.top()+l;
}
cout << ans << endl;
}
