#pragma GCC optimize("unroll-loops,Ofast,O3")
#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define spc << " " <<
#define endl "\n"
#define all(x) x.begin(), x.end()
#define int long long
#define ii pair<long long,int>
#define vi vector<int>
#define vii vector<ii>
#define st first
#define nd second
#define inf 1e15
#define MOD 1000000007
#define MX 1505
using namespace std;
void solve(){
int n,m; cin >> n >> m;
int arr[n+1];
for(int i=1; i<=n; i++){
cin >> arr[i];
arr[i]=m*i-arr[i];
}
vi cur;
for(int i=1; i<=n; i++){
if(arr[i]<0) continue;
auto it=upper_bound(all(cur), arr[i]);
if(it==cur.end()) cur.pb(arr[i]);
else cur[it-cur.begin()]=arr[i];
}
cout << n-cur.size() << endl;
}
signed main(){
ios_base::sync_with_stdio(false);cin.tie(0);
#ifdef Local
freopen("in","r",stdin);
freopen("out","w",stdout);
#endif
/*freopen(".in","r",stdin);
freopen(".out","w",stdout);*/
int t=1;
//cin >> t;
while(t--) solve();
}
