#include <bits/stdc++.h>
#define ent '\n'
#define int long long

using namespace std;
typedef long long ll;

const int maxn = 1e6 + 12;
const int mod = 998244353;

multiset<int> st[maxn];
int t[maxn * 4];
int suff[maxn];
int dp[maxn];
int a[maxn];
int n, m, k;

void upd(int v, int tl, int tr, int pos) {
    if(tl == tr) {
        t[v] = 0;
        if(st[tl].size() != 0) {
            t[v] = *st[tl].rbegin();
        }
        return;
    }
    int mid = tl + tr >> 1;
    if(pos <= mid) {
        upd(v * 2, tl, mid, pos);
    }
    else {
        upd(v * 2 + 1, mid + 1, tr, pos);
    }
    t[v] = max(t[v * 2], t[v * 2 + 1]);
}

int get(int v, int tl, int tr, int l, int r) {
    if(tl > r || l > tr) return 0;
    if(tl >= l && tr <= r) return t[v];
    int mid = tl + tr >> 1;
    return max(get(v * 2, tl, mid, l, r), get(v * 2 + 1, mid + 1, tr, l, r));
}

void solve() {
    cin >> n >> k;
    vector<int> ord;
    for(int i = 1; i <= n; i++) {
        cin >> a[i];
        ord.push_back(a[i]);
    }
    sort(ord.begin(), ord.end());
    ord.resize(unique(ord.begin(), ord.end()) - ord.begin());
    for(int i = 1; i <= n; i++) {
        a[i] = lower_bound(ord.begin(), ord.end(), a[i]) - ord.begin() + 1;
    }
    for(int x = n; x; x--) {
        int mx = 0;
        for(int i = x; i <= n; i++) {
           dp[i] = get(1, 1, n, 1, a[i] - 1) + 1;
            st[a[i]].insert(dp[i]);
            upd(1, 1, n, a[i]);
            if(i > k) {
                st[a[i - k]].erase(dp[i - k]);
                upd(1, 1, n, a[i - k]);
            }
            mx = max(mx, dp[i] + suff[i + 1]);
        }
        suff[x] = mx;
        for(int i = 1; i <= n; i++) {
            dp[i] = 0;
            st[i].clear();
        }
        for(int i = 1; i <= n * 4; i++) {
            t[i] = 0;
        }
    }
    cout << suff[1] << '\n';
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
//     cin >> t;
    while(t--) {
        solve();
    }
}