#include <bits/stdc++.h>
#define int long long
using namespace std;
int n, m;
#define MAXN 200005
int a[MAXN];
int b[MAXN];
void solve(){
cin >> n >> m;
for (int i = 1; i <= n; ++i){
cin >> a[i];
b[i] = m * i - a[i];
}
vector<int> v;
for (int i = 1; i <= n; ++i){
if (b[i] < 0) continue;
auto it = upper_bound(v.begin(), v.end(), b[i]);
if (it == v.end()) {
v.push_back(b[i]);
} else *it = b[i];
}
cout << n - v.size();
}
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
solve();
return 0;
}
