#include "bits/stdc++.h"
using namespace std;
#define INF 1000000000
#define INFLL 1000000000000000000ll
#define EPS 1e-9
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define pb push_back
#define fi first
#define sc second
using i64 = long long;
using u64 = unsigned long long;
using ld = long double;
using ii = pair<int, int>;
using i128 = __int128;
int main(int argc, char* argv[]) {
ios_base :: sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
vector<int> h(n + 1, 0), coords(n + 1), bit(n + 2, INF);
for(int i = 1; i <= n; ++i) cin >> h[i];
for(int i = 0; i <= n; ++i) coords[i] = h[i] - m * i;
sort(all(coords));
auto get = [&](int x) {
int k = lower_bound(all(coords), x) - coords.begin();
return (int)coords.size() - k - 1;
};
auto upd = [&](int k, int x) {
for(++k; k <= (int)coords.size(); k += k & -k) bit[k] = min(bit[k], x);
};
auto query = [&](int k) {
int ans = INF;
for(++k; k > 0; k -= k & -k) ans = min(ans, bit[k]);
return ans;
};
/*
0 1 1 1 0
hi hi + m hi + 2m hi + 3m hj
hj <= hi + m * (j - i)
hj - mj <= hi - mi
*/
upd(get(0), 0);
int ans = n;
for(int i = 1; i <= n; ++i) {
int x = get(h[i] - i * m);
int cnt = query(x) + i - 1;
upd(x, cnt - i);
ans = min(ans, cnt + n - i);
}
cout << ans << '\n';
return 0;
}
