#include <bits/stdc++.h>
using namespace std;
#define ll long long
int solve(const vector<int>& v)
{
vector<int> tmp;
for(int i : v)
{
int it = upper_bound(tmp.begin(), tmp.end(), i) - tmp.begin();
if(it == tmp.size()) tmp.push_back(i);
else tmp[it] = i;
}
return tmp.size();
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m;
cin >> n >> m;
vector<int> p(n);
for(int i=0; i<n; i++)
{
cin >> p[i];
}
vector<int> nc;
for(int i=1; i<=n; i++)
{
if(m*i >= p[i-1])
{
nc.push_back(m*i - p[i-1]);
}
}
cout << n - solve(nc) << "\n";
return 0;
}
