#include <bits/stdc++.h>
using namespace std;
int main(){
//freopen("1.in","r",stdin);
long long n,jump;
cin>>n>>jump;
vector<long long> a(n);
for (long long i=0;i<n;i++) cin>>a[i];
reverse(a.begin(),a.end());
long long curr=0;
for (long long i=0;i<n;i++) {
a[i]+=curr;
curr+=jump*i;
}
// for (auto num:a) cout<<num<<" ";
// cout<<"\n";
vector<long long> dp;
for (auto num:a) {
auto it = upper_bound(dp.begin(),dp.end(),num);
if (it==dp.end()) dp.push_back(num);
else *it = num;
}
// for (auto num:dp) cout<<num<<" ";
// cout<<"\n";
cout<<n-dp.size()<<"\n";
}
