#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;
#define all(x) x.begin(), x.end()
#define sz(x) ((int) ((x).size()))
#define pb push_back
#define F first
#define S second
#define FIO ios_base::sync_with_stdio(false); cin.tie(0)
const int N = 3e5 + 10;
const int off = 1 << 19;
pii tr[off * 4];
void update(int node, int val) {
node += off;
tr[node] = {val, node - off};
while (node /= 2) {
tr[node] = max(tr[node * 2], tr[node * 2 + 1]);
}
}
pii query(int l, int r, int node = 1, int x = 0, int y = off - 1) {
if (l > y or x > r) return {-INT_MAX, 0};
if (l <= x and y <= r) return tr[node];
return max(query(l, r, node * 2, x, (x + y) / 2), query(l, r, node * 2 + 1, (x + y) / 2 + 1, y));
}
pii tr2[off * 4];
ll lazy[off * 4];
ll odz[off * 4];
void prop(int node, int x, int y) {
if (tr2[node].F == INT_MAX) {
odz[node] = 0;
lazy[node] = 0;
}
if (lazy[node] != 0) tr2[node] = {lazy[node], x};
else tr2[node].F += odz[node];
if (x != y) {
if (odz[node]) {
prop(node * 2, x, (x + y) / 2);
prop(node * 2 + 1, (x + y) / 2 + 1, y);
odz[node * 2] += odz[node];
odz[node * 2 + 1] += odz[node];
} else if (lazy[node]) {
odz[node * 2] = 0;
odz[node * 2 + 1] = 0;
lazy[node * 2] = lazy[node];
lazy[node * 2 + 1] = lazy[node];
}
}
odz[node] = 0;
lazy[node] = 0;
}
void ov(int l, int r, int val, int node = 1, int x = 0, int y = off - 1) {
prop(node, x, y);
if (l > y or x > r) return;
if (l <= x and y <= r) {
lazy[node] = val;
prop(node, x, y);
if (x == y) {
tr2[node].F = val;
tr2[node].S = x;
}
return;
}
ov(l, r, val, node * 2, x, (x + y) / 2);
ov(l, r, val, node * 2 + 1, (x + y) / 2 + 1, y);
tr2[node] = min(tr2[node * 2], tr2[node * 2 + 1]);
}
void add(int l, int r, int delta, int node = 1, int x = 0, int y = off - 1) {
prop(node, x, y);
if (l > y or x > r) return;
if (l <= x and y <= r) {
odz[node] = delta;
prop(node, x, y);
return;
}
add(l, r, delta, node * 2, x, (x + y) / 2);
add(l, r, delta, node * 2 + 1, (x + y) / 2 + 1, y);
tr2[node] = min(tr2[node * 2], tr2[node * 2 + 1]);
}
pii find(int l, int r, int node = 1, int x = 0, int y = off - 1) {
prop(node, x, y);
if (l > y or x > r) return {INT_MAX, 0};
if (l <= x and y <= r) return tr2[node];
return min(find(l, r, node * 2, x, (x + y) / 2), find(l, r, node * 2 + 1, (x + y) / 2 + 1, y));
}
int n, d;
int a[N];
set<pii> s[N];
int main() {
FIO;
for (int i = 0; i < off * 4; i++) {
tr2[i] = {INT_MAX, 0};
}
cin >> n >> d;
set<int> se;
map<int, int> conv;
for (int i = 0; i < n; i++) {
cin >> a[i];
se.insert(a[i]);
}
int cur = 0;
for (int x : se) {
conv[x] = ++cur;
}
for (int i = 0; i < n; i++) {
a[i] = conv[a[i]];
}
int ans = 0;
for (int i = 0; i < n; i++) {
add(1, n, -1);
pii k = find(0, n);
while (k.F < 0) {
int val = k.S;
update(val, 0);
ov(val, val, INT_MAX);
while (sz(s[val]) and prev(s[val].end())->S + d < i) {
s[val].erase(prev(s[val].end()));
}
if (sz(s[val])) {
auto iter = prev(s[val].end());
update(val, iter->F);
ov(val, val, iter->S + d - i);
}
k = find(1, n);
}
ov(a[i], n, d);
int val = query(0, a[i] - 1).F + 1;
if (query(a[i], a[i]).F <= val) {
update(a[i], val);
ov(a[i], a[i], d);
} else {
s[a[i]].insert({val, i});
}
if (i + d + 1 >= n) ans = max(ans, (int)query(1, n).F);
}
cout << ans << endl;
return 0;
}
