#include <bits/stdc++.h>
using i64 = long long;
const int inf = 1E9;
const int M = 800000;
int mx[M];
void Modify(int p, int l, int r, int i, int v) {
mx[p] = std::max(mx[p], v);
if (l == r) {
return;
}
int mid = (l + r) / 2;
if (i <= mid) {
Modify(p * 2, l, mid, i, v);
} else {
Modify(p * 2 + 1, mid + 1, r, i, v);
}
}
int Get(int p, int l, int r, int ql, int qr) {
if (l > r || l > qr || r < ql) {
return -inf;
}
if (ql <= l && r <= qr) {
return mx[p];
}
int mid = (l + r) / 2;
return std::max(Get(p * 2, l, mid, ql, qr), Get(p * 2 + 1, mid + 1, r, ql, qr));
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int n, m;
std::cin >> n >> m;
n += 1;
std::vector<int> a(n);
for (int i = 1; i < n; i++) {
std::cin >> a[i];
a[i] -= i * m;
}
std::vector<int> xs = a;
std::sort(xs.begin(), xs.end());
xs.erase(std::unique(xs.begin(), xs.end()), xs.end());
int k = (int) xs.size();
for (int i = 0; i < n; i++) {
a[i] = std::lower_bound(xs.begin(), xs.end(), a[i]) - xs.begin();
}
std::vector<int> dp(n, -inf);
dp[0] = 1;
for (int i = 0; i < M; i++) {
mx[i] = -inf;
}
Modify(1, 0, k, a[0], 1);
for (int i = 1; i < n; i++) {
dp[i] = Get(1, 0, k, a[i], k) + 1;
Modify(1, 0, k, a[i], dp[i]);
}
std::cout << n - *std::max_element(dp.begin(), dp.end()) << "\n";
return 0;
}
