#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define FAST_IO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define pb push_back
#define all(x) begin(x), end(x)
#define umap unordered_map
#define space " "
#define TEST_CASES int a; cin >> a; for (int i = 0; i < a; i++) {solve(); cout << endl;}
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
void solve() {
int n; ll m; cin >> n >> m;
vector<ll> dp;
for (int i = 1; i <= n; i++) {
ll x; cin >> x;
if (x <= m * i) {
auto it = upper_bound(all(dp), -x + m * i);
if (it == dp.end()) {
dp.pb(-x + m * i);
}
else {
*it = -x + m * i;
}
}
}
cout << n - dp.size();
}
int main() {
FAST_IO;
//freopen("pcb.in", "r", stdin);
//freopen("pcbout", "w", stdout);
//TEST_CASES;
solve(); cout << endl;
/*int a; cin >> a;
for (int i = 1; i <= a; i++){
cout << "Case #" << i << ": ";
solve();
cout << endl;
}*/
}
