#include <bits/stdc++.h>
using namespace std;
const int N = 200100;
const long long inf = 1e8;
long long bit[N];
void up(int x) {
  while (x < N) {
    bit[x]++;
    x += (x & -x);
  }
}
int query(int x) {
  int sum = 0;
  while (x) {
    sum += bit[x];
    x -= (x & -x);
  }
  return sum;
}
pair<int, int> a[N];
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, t;
  cin >> n >> t;
  for (int i = 0; i < n; ++i) {
    cin >> a[i].first;
    a[i].first -= i + 1;
    a[i].second = i + 1;
  }
  sort(a, a + n);
  int ans = 0;
  for (int i = 0; i < n; ++i) {
    up(a[i].second);
    if (a[i].first < 0 && t > 1) ans = max(ans, query(min(t - 1, n)));
    if (a[i].first + 1 < t && a[i].first >= 0)
      ans = max(ans, query(min(t - a[i].first - 1, n)));
  }
  cout << ans << '\n';
  return 0;
}
