#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define pb push_back
/* Segment Tree */
template <class S, S (*op)(S, S), S (*e)()>
struct segtree {
/* S op(S a, S b) {} -> Combine values */
/* S e() {} -> Initial value (0) */
int _n;
vector<S> d;
segtree() : segtree(0) {}
explicit segtree(int n) : segtree(vector<S>(n, e())) {}
explicit segtree(vector<S> v) : _n(int(v.size())) {
d.assign(4 * _n, e());
build(v);
}
void build(vector<S>& a, int v = 1, int tl = 0, int tr = -1) {
if (tr == -1) tr = _n - 1;
if (tl == tr) {
d[v] = a[tl];
} else {
int tm = (tl + tr) / 2;
build(a, v * 2, tl, tm);
build(a, v * 2 + 1, tm + 1, tr);
d[v] = op(d[v * 2], d[v * 2 + 1]);
}
}
void set(int pos, S new_val, int tl = 0, int tr = -1, int v = 1) {
assert(0 <= pos && pos < _n);
if (tr == -1) tr = _n - 1;
if (tl == tr) {
d[v] = new_val;
} else {
int tm = (tl + tr) / 2;
if (pos <= tm)
set(pos, new_val, tl, tm, v * 2);
else
set(pos, new_val, tm + 1, tr, v * 2 + 1);
d[v] = op(d[2 * v], d[2 * v + 1]);
}
}
S prod(int l, int r, int tl = 0, int tr = -1, int v = 1) {
if (tr == -1) tr = _n - 1;
if (r < l) return e();
if (l == tl && r == tr) return d[v];
int tm = (tl + tr) / 2;
return op(prod(l, min(r, tm), tl, tm, 2 * v),
prod(max(l, tm + 1), r, tm + 1, tr, 2 * v + 1));
}
// new - might have bugs
size_t prod_lower_bound(S x, int tl = 0, int tr = -1, int v = 1,
S acc = e()) {
if (tr == -1) {
if (prod(0, _n - 1) < x) return _n;
tr = _n - 1;
}
if (tl == tr) return tl;
int tm = (tl + tr) / 2;
if (op(acc, d[2 * v]) < x)
return prod_lower_bound(x, tm + 1, tr, 2 * v + 1, op(acc, d[2 * v]));
else
return prod_lower_bound(x, tl, tm, 2 * v, acc);
}
size_t prod_upper_bound(S x, int tl = 0, int tr = -1, int v = 1,
S acc = e()) {
if (tr == -1) {
if (prod(0, _n - 1) <= x) return _n;
tr = _n - 1;
}
if (tl == tr) return tl;
int tm = (tl + tr) / 2;
if (op(acc, d[2 * v]) <= x)
return prod_upper_bound(x, tm + 1, tr, 2 * v + 1, op(acc, d[2 * v]));
else
return prod_upper_bound(x, tl, tm, 2 * v, acc);
}
};
/* End: Segment Tree */
ll op(ll a, ll b) { return max(a, b); }
ll e() { return 0; }
int main() {
int n, d;
cin >> n >> d;
vector<int> v(n);
for (int i = 0; i < n; i++) cin >> v[i];
do {
// compression
vector<int> dd = v;
sort(dd.begin(), dd.end());
dd.resize(unique(dd.begin(), dd.end()) - dd.begin());
for (int i = 0; i < n; i++) {
v[i] = lower_bound(dd.begin(), dd.end(), v[i]) - dd.begin();
}
} while (false);
int mx = *max_element(v.begin(), v.end());
if (d == 1) {
stack<int> s;
int ans = 0;
for (int i = n; i--;) {
while (s.size() && s.top() <= v[i]) s.pop();
s.push(v[i]);
ans = max(ans, (int)s.size());
}
cout << ans << endl;
return 0;
}
if (d == n) {
segtree<ll, op, e> st(mx+1);
for (int i = 0; i < n; i++) {
st.set(v[i], max(st.prod(v[i],v[i]), st.prod(0, v[i]-1) + 1));
}
cout << st.prod(0, mx) << endl;
return 0;
}
#ifdef HZLOCAL
cout << mx << endl;
cout << "V: ";
for (auto x : v) cout << x << " ";
cout << endl;
#endif
vector<vector<int>> dp(n, vector<int>(mx + 1, 0));
vector<multiset<int>> cmax(mx + 1);
for (int i = 0; i < n; i++) {
int prev, cur = 0;
for (int j = 0; j <= mx; j++) {
prev = cur;
if (cmax[j].size()) {
cur = max(cur, *cmax[j].rbegin());
}
if (j < v[i]) continue;
int candidate = max(cur, j ? dp[i][j - 1] : 0);
if (v[i] == j) candidate = max(candidate, j ? prev + 1 : 1);
dp[i][j] = candidate;
}
if (i >= d) {
for (int j = 0; j <= mx; j++) {
cmax[j].erase(cmax[j].find(dp[i - d][j]));
}
}
for (int j = 0; j <= mx; j++) {
cmax[j].insert(dp[i][j]);
}
}
#ifdef HZLOCAL
for (auto x : dp) {
for (auto y : x) cout << y << " ";
cout << endl;
}
#endif
cout << *max_element(dp[n - 1].begin(), dp[n - 1].end()) << endl;
}
