#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define vi vector<int>
vi tree;
void update(int v, int tl, int tr, int p, int k) {
if (tl == tr) tree[v] = min(tree[v], k);
else {
int tm = (tl+tr)/2;
if (p <= tm) update(2*v, tl, tm, p, k);
else update(2*v+1, tm+1, tr, p, k);
tree[v] = min(tree[2*v], tree[2*v+1]);
}
}
int query(int v, int tl, int tr, int l, int r) {
if (l > r) return INT32_MAX;
if (tl == l && tr == r) return tree[v];
int tm = (tl+tr)/2;
int a = query(2*v, tl, tm, l, min(r, tm));
int b = query(2*v+1, tm+1, tr, max(l, tm+1), r);
return min(a, b);
}
void solve() {
int n, m;
cin >> n >> m;
vector<int> a(n);
for (int &x : a) cin >> x;
a.insert(a.begin(), 0);
a.push_back(INT32_MIN);
n += 2;
tree.resize(4*n, INT32_MAX);
vi s;
for (int i = 0; i < n; i++) {
s.push_back(a[i] - m * i);
}
map<int, int> comp;
sort(s.begin(), s.end());
int ind = 0;
for (int i = 0; i < n; i++) {
if (comp.count(s[i])) continue;
comp[s[i]] = ind;
ind++;
}
vi dp(n, INT32_MAX);
dp[0] = 0;
update(1, 0, n-1, comp[0], 0);
for (int i = 1; i < n; i++) {
if (a[i] - a[i-1] <= m) dp[i] = dp[i-1];
int ind = comp[(a[i] - m * i)];
int x = query(1, 0, n-1, ind, n-1);
dp[i] = min(dp[i], x + i - 1);
update(1, 0, n-1, ind, dp[i] - i);
// cerr << i << ' ' << x << ' ' << dp[i] << endl;
}
cout << dp[n-1];
}
/*
a_i - a_j <= (i - j) * m
a_i - a_j <= mi - mj
a_i - mi <= a_j - mj
200 - 1200 >= 1000 - 1600
dp_j + (i - j)
dp_j - j
look for index j such that:
dp_j - j is minimized
a_i - mi <= a_j - mj
*/
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
}
