#include <bits/stdc++.h>
#define F first
#define S second
using namespace std;
using ll = long long;
using pi = pair<int, int>;
using vi = vector<int>;
template<class T> bool ckmin(T& a, T b) { return b < a ? a = b, true : false; }
template<class T> bool ckmax(T& a, T b) { return a < b ? a = b, true : false; }
int main() {
ios::sync_with_stdio(0); cin.tie(0);
ll n, m; cin >> n >> m;
vector<ll> a(n + 1);
for (int i = 1; i <= n; ++i) cin >> a[i];
for (int i = 1; i <= n; ++i) a[i] -= i * m;
vector<int> dp(n + 1, -1e9);
dp[0] = 1;
for (int i = 1; i <= n; ++i) {
for (int j = 0; j < i; ++j) {
if (a[i] < a[j]) {
dp[i] = max(dp[i], dp[j] + 1);
}
}
}
int ans = 0;
for (int i = 1; i <= n; ++i) ckmax(ans, dp[i]);
cout << n - ans << "\n";
}
