#include <bits/stdc++.h>
// author : a1abay
#define all(v) v.begin(), v.end()
#define GCD(a, b) __gcd(a, b)
#define LCM(a, b) (a*b / (__gcd(a, b)))
#define int ll
typedef long long ll;
typedef long double ld;
const int inf = 1e9 + 7;
const int inff = (int)1e18 + 7;
const int sz = 2e5 + 5;
using namespace std;
int n, m;
int a[sz];
vector<int> v;
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for(int i = 1; i <= n; i++)
{
cin >> a[i];
a[i] -= i * m;
}
for(int i = n; i > 0; i--)
{
if(a[i] > 0)continue;
auto lb = upper_bound(all(v), a[i]);
if(lb == v.end())v.push_back(a[i]);
else v[lb - v.begin()] = a[i];
}
cout << n - v.size();
}
