#include <bits/stdc++.h>
#define int long long
using namespace std;
const int maxs=2e4+10;
const int maxn=1e3+10;
const int inf=1e18+10;
signed main()
{
ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
int n, m; cin >> n >> m;
vector<int>dp;
for(int i=1;i<=n;i++){
int a; cin >> a;
if(a>m*i) continue;
int at=m*i-a;
int id=upper_bound(dp.begin(),dp.end(),at)-dp.begin();
//cout << at << " " << id << " " << dp.size() << endl;
if(id==dp.size()) dp.push_back(at);
else dp[id]=at;
}
cout << n-dp.size() << endl;
return 0;
}
