#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5, INF = 1e9;
int n, m, ans, a[N], dp[N];
struct sparseseg{
struct node{
int v;
node *l, *r;
node(int x): v(x), l(0), r(0){}
};
typedef node* pnode;
pnode rt = 0;
void upd(pnode &k, int l, int r, int pos, int x){
if(!k) k = new node(INF);
if(l == r) return k->v = x, void();
int md = l + (r - l) / 2;
if(pos <= md) upd(k->l, l, md, pos, x);
else upd(k->r, md + 1, r, pos, x);
k->v = min(k->l ? k->l->v : INF, k->r ? k->r->v : INF);
}
int qry(pnode k, int l, int r, int ql, int qr){
if(!k || qr < l || r < ql) return INF;
if(ql <= l && r <= qr) return k->v;
int md = l + (r - l) / 2;
return min(qry(k->l, l, md, ql, qr), qry(k->r, md + 1, r, ql, qr));
}
}s;
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m;
for(int i = 1;i<=n;i++) cin >> a[i];
s.upd(s.rt, -INF, INF, 0, 0);
for(int i = 1;i<=n + 1;i++){
dp[i] = s.qry(s.rt, -INF, INF, a[i] - m * i, INF) + i - 1;
s.upd(s.rt, -INF, INF, a[i] - m * i, dp[i] - i);
}
cout << dp[n + 1];
}
