#include <bits/stdc++.h>
#define int long long
#define vec vector
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define sq(x) (x)*(x)
#define fast_io ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
using namespace std;
typedef pair<int,int> PII;
int f(int k, int b, int x){
return k*x+b;
}
int k, x, b, y, sum;
// const int M = 1000;
// const int C = 200;
signed main(){
//ifstream cin("input.txt");
//ofstream cout("output.txt");
fast_io;
int n, h;
cin >> n >> h;
vec < int > q(n);
vec < int > w;
for(auto &i: q) cin >> i, sum += i;
// vec < vec < int > > dp(n, vec < int > (M, 1e18));
// for(int i = 0; i < M; ++i)
// dp[0][i] = abs(i-q[0]);
// for(int i = 1; i < n; ++i){
// for(int j = 0; j < M; ++j){
// for(int k = max(0LL, j-h); k <= min(M-1, j+h); ++k)
// dp[i][j] = min(dp[i-1][k]+abs(j-q[i]), dp[i][j]);
// }
// }
// for(int k = 0; k < n; ++k){
// auto i = dp[k];
// int r = i[1]-i[0];
// for(int j = 2; j < M; ++j){
// while(i[j]-i[j-1] != r){
// cout << j-1 << " ";
// r++;
// }
// }
// cout << "\n";
// }
// cout << "\n";
multiset < int > one;
multiset < int > two;
int left = 0;
int right = 0;
for(int i = 0; i < n; ++i){
one.insert(q[i]-left);
one.insert(q[i]-left);
while(sz(one) > sz(two)){
auto it = one.end();
it--;
int adder = *it;
adder -= right;
adder += left;
two.insert(adder);
one.erase(one.find(*it));
}
while(sz(one) < sz(two)){
int adder = *two.begin();
adder += right;
adder -= left;
one.insert(adder);
two.erase(two.find(adder));
}
auto it = one.end();
it--;
while((*it)+left > (*two.begin())+right){
two.insert(*it+left-right);
one.erase(it);
one.insert(*two.begin()+right-left);
two.erase(two.begin());
}
// cout << q[i] << " :: ";
// for(auto &j: one) cout << j+left << " ";
// for(auto &j: two) cout << j+right << " ";
// cout << "\n";
left -= h;
right += h;
}
left += h;
right -= h;
vec < int > fin;
for(auto &i: one) fin.pb(i+left);
for(auto &i: two) fin.pb(i+right);
// for(auto &i: fin) cout << i << " ";
// cout << "\n";
b = -sum;
for(int i = 0; i < n; ++i)
b -= i*h;
k = n;
int ans = 1e18;
for(int i = sz(fin)-1; i >= 0; --i){
x = fin[i];
y = k*x+b;
ans = min(ans, y);
k--;
b = y-k*x;
}
cout << ans;
return 0;
}
