// Born_To_Laugh - Hughie Do
#include <bits/stdc++.h>
#define alle(sth) sth.begin(), sth.end()
using namespace std;
typedef long long ll;
[[maybe_unused]] const ll MOD = 998244353, INF = 1e9 + 7;
void solve(){
int n, m;cin >> n >> m;
vector<int> a(1, 0);
for(int i=1; i<=n; ++i){
int x;cin >> x;
if(x > m * i)continue;
a.push_back(m * i - x);
}
vector<int> dp;
for(int i=1; i<(int)a.size(); ++i){
int pos = upper_bound(alle(dp), a[i]) - dp.begin();
if(pos == (int)dp.size()){
dp.push_back(a[i]);
}
else{
dp[pos] = a[i];
}
}
cout << n - dp.size() << '\n';
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
