#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <utility>
#include <cmath>
#include <numeric>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pb push_back
#define endl "\n"
#define all(x) x.begin(), x.end()
const int M = 200007;
const ll inf = 1e18;
const ll mod = 1e9 + 7;
const double pi = acos(-1);
vector <ll> v;
ll n, m;
int main()
{
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n >> m;
for(int i = 1; i <= n; ++i){
ll x;
cin >> x;
x = m * i - x;
if(x < 0) continue;
auto it = upper_bound(v.begin(), v.end(), x);
if(it == v.end()) v.pb(x);
else *it = x;
}
cout << n - v.size() << endl;
return 0;
}
// Don't forget special cases. (n = 1?)
// Look for the constraints. (Runtime array? overflow?)
