#include <bits/stdc++.h>
using namespace std;
#define int long long
#define name "ojuz"
#define MAXN 200005
#define pb push_back
#define pf push_front
#define ll long long
#define ii pair<int, int>
#define fs first
#define sc second
#define ill pair<int, ll>
#define lli pair<ll, int>
#define llll pair<ll, ll>
#define all(v) v.begin(),v.end()
#define uni(v) v.erase(unique(all(v)),v.end())
#define bit(n,i) (((n)>>(i))&1)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define MASK(i) (1LL<<(i))
const int INF=1e9;
const int MOD=1e9+7;
void add(int &u, int v){
u+=v;
if (u>=MOD) u-=MOD;
}
void sub(int &u, int v){
u-=v;
if (u<0) u+=MOD;
}
void minimize(int &u, int v){
u=min(u,v);
}
void maximize(int &u, int v){
u=max(u,v);
}
long long Rand(long long l, long long r){
ll tmp=0;
FOR(i,1,4) tmp=((tmp<<15)^(((1<<15)-1)&rand()));
return l+tmp%(r-l+1);
}
int n,m;
int a[MAXN];
int bit[MAXN],dp[MAXN];
void update(int x, int val){
for (; x>0; x-=x&-x) maximize(bit[x],val);
}
int get(int x){
int res=-INF;
for (; x<MAXN; x+=x&-x) maximize(res,bit[x]);
return res;
}
int32_t main()
{
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
cin>>n>>m;
FOR(i,1,n) cin>>a[i];
FOR(i,1,n) a[i]-=i*m;
vector<int> store;
FOR(i,0,n) store.pb(a[i]);
sort(all(store));
uni(store);
FOR(i,0,n) a[i]=lower_bound(all(store),a[i])-store.begin()+1;
memset(bit,-0x3f,sizeof(bit));
update(a[0],0);
/*
FOR(i,0,n) cout<<a[i]<<" ";
cout<<"\n";
*/
FOR(i,1,n){
if (a[i]>a[0]) continue;
dp[i]=get(a[i]);
if (dp[i]>=0) dp[i]++;
update(a[i],dp[i]);
}
cout<<n-(*max_element(dp+1,dp+n+1));
return 0;
}
