#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define TEST
const int INF = 2e9;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int N{}, M{};
cin >> N >> M;
vector<int> poles(N);
for (int i = 0; i < N; i++) {
cin >> poles[i];
poles[i]=(M*i+i)-poles[i];
}
//longest increasing subsequence
vector<int> dp(N+1,INF); // d_i(j)
dp[0] = -INF;
for (int i = 0; i < N; i++) {
int pos =upper_bound(dp.begin(), dp.end(), poles[i]) - dp.begin();
if (dp[pos-1] < poles[i]) {
dp[pos]=poles[i];
}
}
int max_len{0};
for (int i = 1; i <= N; i++) {
if (dp[i]!=INF) {
max_len=i;
}
else {
break;
}
}
cout << max_len << "\n";
return 0;
}
