#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using vi = vector<int>;
vi A;
int N, M;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> N >> M;
A = vi(2+N);
A[1] = 0;
for(int i = 2; i <= N+1; i++) cin >> A[i];
vi I(1+N);
for(int i = 0; i <= N; i++) I[i] = i+1;
sort(I.begin(), I.end(), [] (int l, int r)
{
if(A[l] - M*l == A[r] - M*r) return l < r;
else return A[l] - M*l > A[r] - M*r;
});
vi DP(1+N+1, 5'000'000);
vi BIT(1+N+1, 5'000'000);
int ans = 5'000'000;
for(int i: I)
{
if(i == 1)
DP[i] = 0;
else
{
for(int x = i-1; x >= 1; x -= x&-x)
{
DP[i] = min(DP[i], BIT[x] + i-1);
}
}
for(int x = i; x <= N+1; x += x&-x)
BIT[x] = min(BIT[x], DP[i] - i);
ans = min(ans, DP[i] + N+1-i);
}
cout << ans << '\n';
}
