#include <iostream>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <vector>
#include <random>
#include <algorithm>
#include <climits>
#include <cmath>
#include <queue>
#include <iomanip>
#include <memory.h>
#include <cassert>
using namespace std;
const long long LINF = -1e9;
struct Slope
{
multiset<long long> L, R;
long long dl, dr;
long long b;
Slope()
{
dl = dr = b = 0;
}
void balance()
{
while (L.size() > R.size())
{
long long x = *L.rbegin() + dl;
L.erase(--L.end());
R.insert(x - dr);
}
while (R.size() > L.size())
{
long long x = *R.begin() + dr;
R.erase(R.begin());
L.insert(x - dl);
}
}
void Expand(long long delta)
{
dl -= delta;
dr += delta;
b -= delta * L.size();
}
void addFirst(long long x)
{
b += x - LINF;
L.insert(x);
R.insert(x);
}
void add(long long x)
{
b += x - LINF;
if (x <= *L.rbegin() + dl)
{
L.insert(x - dl);
L.insert(x - dl);
}
else
{
R.insert(x - dr);
R.insert(x - dr);
}
balance();
}
long long getMin()
{
long long prev = LINF;
long long res = b;
long long slope = -L.size();
for (long long x : L)
{
res += slope * (x + dl - prev);
prev = x + dl;
++slope;
}
return res;
}
};
int main()
{
ios_base :: sync_with_stdio (false);
cin.tie(NULL);
#ifdef TESTMARKLOCAL
freopen("in.txt", "r", stdin);
#endif
int n, h;
cin >> n >> h;
Slope res;
for (int i = 0; i < n; ++i)
{
int x;
cin >> x;
if (i == 0)
res.addFirst(x);
else
{
res.Expand(h);
res.add(x);
}
}
cout << res.getMin() << '\n';
return 0;
}
