#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
typedef pair<ll,ll> pi;
typedef vector <int> vi;
typedef vector <pi> vpi;
typedef pair<pi,ll> pii;
typedef set <ll> si;
typedef long double ld;
#define f first
#define s second
#define FOR(i,s,e) for(ll i=s;i<=ll(e);++i)
#define DEC(i,s,e) for(ll i=s;i>=ll(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0)
#define maxn 1000001
#define INF (ll)1e13
#define DEBUG 0
#define MOD 1000000007
//#define getchar_unlocked _getchar_nolock
int N,H,t;
priority_queue <int> leftpq;
priority_queue <int,vector <int>, greater <int> > rightpq;
int leftoffset = 0, rightoffset = 0;
int ans = 0;
int32_t main(){
fast;
cin >> N >> H;
cin >> t;
leftpq.push(t-H); rightpq.push(t+H);
FOR(i,2,N){
cin >> t;
if (t <= leftpq.top() + leftoffset) {
ans += abs(t - (leftpq.top() + leftoffset));
leftpq.push(t-leftoffset); leftpq.push(t-leftoffset);
rightpq.push(leftpq.top()+leftoffset-rightoffset); leftpq.pop();
}else{
if (t >= rightpq.top() + rightoffset) ans += abs(t - (rightpq.top() + rightoffset));
rightpq.push(t-rightoffset); rightpq.push(t-rightoffset);
leftpq.push(rightpq.top()+rightoffset-leftoffset); rightpq.pop();
}
leftoffset -= H; rightoffset += H;
//cout << ans << ' ';
}
cout << ans;
}
