#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
ll i, j, k, n, m, h[200007], mi[200007];
void run(){
cin >> n >> m;
for( i = 1; i <= n; i++) cin >> h[i], mi[i] = n;
mi[0] = 0; mi[n+1] = n;
for( i = 1; i <= n; i++){
if(h[i-1]+m >= h[i]) mi[i] = min(mi[i], mi[i-1]);
for( j = i; j <= n; j++){
if(h[i-1]+(1+j-i)*m+m >= h[j+1]) mi[j+1] = min(mi[j+1], mi[i-1]+(1+j-i));
}
}
cout << min(mi[n], mi[n+1]);
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
// int tt; cin >> tt; while(tt--)
run();
}
