#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define all(a) a.begin(),a.end()
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef unsigned long long ull;
typedef vector<int> vi;
void solve(){
int n,h; cin >> n >> h;
priority_queue<ll> slope_left;
priority_queue<ll,vector<ll>,greater<ll>> slope_right;
ll off_left = 0, off_right = 0;
ll ans = 0;
int a; cin >> a;
slope_left.push(a);
slope_right.push(a);
off_left = -h;
off_right = h;
for(int i = 1; i < n; i++){
cin >> a;
ll low = a-off_left;
ll up = a-off_right;
if(low < slope_left.top()){
ans += slope_left.top() - low;
slope_left.push(low);
slope_left.push(low);
ll b = slope_left.top(); slope_left.pop();
b += off_left;
slope_right.push(b-off_right);
}else if(up > slope_right.top()){
ans += up - slope_right.top();
slope_right.push(up);
slope_right.push(up);
ll b = slope_right.top(); slope_right.pop();
b += off_right;
slope_left.push(b-off_left);
}else{
slope_left.push(low);
slope_right.push(up);
}
off_left += -h;
off_right += h;
}
cout << ans;
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
int t = 1;
// cin >> t;
while(t--){solve();}
}
