#include<bits/stdc++.h>
using namespace std;
#define Study ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define ll long long
#define ull unsigned long long
#define pb push_back
#define ff first
#define ss second
#define ins insert
#define all(x) x.begin(),x.end()
#define fori(x,y,z) for(ll x=y;x<=z;x++)
const ll INF=1e18;
const ll sz=5e4+10;
const ll mod=1e9+7;
void work(){
ll n,m;
cin>>n>>m;
vector<ll>v(n+10,0);
fori(i,1,n){
cin>>v[i];
}
vector<ll>maxleft;
fori(i,1,n){
if(i*m>=v[i]){
maxleft.pb(i*m-v[i]);
}
}
vector<ll>wedontchange;
for(auto x : maxleft){
ll cr=(upper_bound(all(wedontchange),x))-wedontchange.begin();
if(cr==wedontchange.size())
wedontchange.pb(x);
else
wedontchange[cr]=x;
}
cout<<n-wedontchange.size()<<endl;
}
int main(){
Study;
ll t=1;
//cin>>t;
while(t--){
work();
}
}
