#include <bits/stdc++.h>
constexpr int inf = 1 << 30;
class SegTree {
int n, size;
std::vector<int> data;
void update(int i) {
data[i] = std::max(data[2 * i], data[2 * i + 1]);
}
public:
SegTree(int n_) : n(n_) {
size = 1;
while (size < n) size *= 2;
data.assign(2 * size, -inf);
}
void set(int i, int v) {
i += size;
data[i] = v;
while (i != 1) {
i /= 2;
update(i);
}
}
int fold(int l, int r) {
int res = -inf;
for (l += size, r += size; l < r; l >>= 1, r >>= 1) {
if (l & 1) res = std::max(res, data[l++]);
if (r & 1) res = std::max(res, data[--r]);
}
return res;
}
int get(int i) {
return data[i + size];
}
};
int solve(int D, std::vector<int> A) {
const int N = (int)A.size();
{
// press
auto B = A;
std::sort(B.begin(), B.end());
B.erase(std::unique(B.begin(), B.end()), B.end());
for (auto &e : A) e = (int)(std::lower_bound(B.begin(), B.end(), e) - B.begin()) + 1;
}
std::vector<std::vector<int>> posList(N + 1);
for (int i = 0; i < N; ++i) {
posList[A[i]].push_back(i);
}
std::vector<int> keepLimit(N, N);
std::set<int> sids;
for (int i = D; i < N; ++i) sids.insert(i);
for (int v = 1; v <= N; ++v) {
for (const int i : posList[v]) {
// [i + 1, i + D]
auto itr = sids.upper_bound(i);
while (itr != sids.end() and *itr <= i + D) {
itr = sids.erase(itr);
}
}
for (const int i : posList[v]) {
auto itr = sids.upper_bound(i);
if (itr != sids.end()) {
keepLimit[i] = *itr;
}
}
}
SegTree seg(N + 1);
seg.set(0, 0);
std::vector<std::vector<int>> eraseList(N + 1);
for (int i = 0; i < N; ++i) {
for (const int j : eraseList[i]) {
seg.set(j, -inf);
}
const int f = seg.fold(0, A[i]);
seg.set(A[i], std::max(seg.get(A[i]), f + 1));
eraseList[keepLimit[i]].push_back(A[i]);
}
return seg.fold(0, N + 1);
}
int solveNaive(int D, std::vector<int> A) {
const int N = (int)A.size();
int answer = 1;
for (int bits = 0; bits < (1 << N); ++bits) {
int last = -1;
if (not(bits & (1 << (N - 1)))) {
continue;
}
int res = 0, ma = -1;
for (int i = 0; i < N; ++i) {
if (bits & (1 << i)) {
if (last == -1) {
last = i;
} else {
if (i - last > D) {
res = -1;
break;
}
}
last = i;
if (A[i] > ma) {
++res;
ma = A[i];
}
}
}
answer = std::max(answer, res);
}
return answer;
}
int main() {
int N, D;
std::cin >> N >> D;
std::vector<int> A(N);
for (auto &e : A) {
std::cin >> e;
}
std::cout << solve(D, A) << std::endl;
/*
int N = 15;
int cas = 100;
std::mt19937 mt(100);
std::uniform_int_distribution dist(1, N);
while (cas--) {
std::vector<int> A(N);
for (auto &e : A) e = dist(mt);
int D = dist(mt);
const int a = solveNaive(D, A), b = solve(D, A);
if (a != b) {
std::cout << D << std::endl;
for (const auto e : A) std::cout << e << ' ';
std::cout << std::endl;
}
}*/
}
