// 027 072 207 270 702 720
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define all(x) x.begin(), x.end()
#define fo(i, a, b) for (int i = (a), b_ = (b); i <= b_; ++i)
#define fod(i, a, b) for (int i = (a), b_ = (b); i >= b_; --i)
#define rep(i, n) fo(i, 1, n)
#define per(i, n) fod(i, n, 1)
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
const int N = 1e6+5;
int n, m, a[N], f[N];
bool reach[N];
ll b[N];
void upd(int p, int v) {
for (; p; p -= p & -p)
chmax(f[p], v);
}
int get(int p) {
int tot = 0;
for (; p <= n; p += p & -p)
chmax(tot, f[p]);
return tot;
}
void sol() {
cin >> n >> m;
reach[0] = 1;
vector<ll> z;
rep(i, n) {
cin >> a[i];
b[i] = a[i] - m * i;
z.pb(b[i]);
}
sort(all(z)); z.resize(unique(all(z))-z.begin());
int ans = 0;
rep(i, n) if (b[i] <= 0) {
b[i] = upper_bound(all(z), b[i])-z.begin();
int lns = get(b[i]) + 1;
ans = max(ans, lns);
upd(b[i], lns);
}
cout << n - ans;
}
signed main() {
cin.tie(0) -> sync_with_stdio(0);
// if (fopen("A.inp", "r")) freopen("A.inp", "r", stdin);
int tc = 1, test = 0; // cin >> tc;
while (++test <= tc) sol();
}
