#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
int main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int n;
ll H;
cin >> n >> H;
vll a(n);
for(int i = 0; i < n; i++){
cin >> a[i];
}
ll add = 0LL;
multiset<ll> l;
multiset<ll> r;
l.insert(a[0]);
r.insert(a[0]);
ll mnVal = 0LL;
for(int i = 1; i < n; i++){
add = (ll)add + H;
if(*(--l.end()) - add <= a[i] && a[i] <= *(r.begin()) + add){
l.insert(a[i] + add);
r.insert(a[i] - add);
}else if(*(--l.end()) - add > a[i]){
ll val = *(--l.end()) - add;
l.insert((ll)a[i] + add);
l.erase(--l.end());
r.insert((ll)val - add);
mnVal += abs(a[i] - val);
}else{
ll val = *(r.begin()) + add;
r.insert((ll)a[i] - add);
r.erase(r.begin());
l.insert((ll)val + add);
mnVal += abs(a[i] - val);
}
}
// cout << add << '\n';
// cerr << "L\n";
// for(auto ele : l){
// cout << ele - add << '\n';
// }
// cerr << "R\n";
// for(auto ele : r){
// cout << ele + add << '\n';
// }
cout << mnVal << '\n';
return 0;
}
