// Homura Akemi a.k.a. Starrykiller (/user/235125)
// I love Madoka Kaname forever! 
#include <bits/stdc++.h>

using namespace std;

template<typename L, typename R>
auto range(L l, R r) { return views::iota(l,r); }
auto rev=views::reverse;

template<typename T>
_GLIBCXX_ALWAYS_INLINE void chmax(T &a, T b) { a=max(a,b); }
template<typename T>
_GLIBCXX_ALWAYS_INLINE void chmin(T &a, T b) { a=min(a,b); }
// #define int long long

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    int n, k; cin>>n>>k;
    vector<int> a(n); for (auto &i: a) cin>>i;
    map<int,vector<int>> pos;
    for (auto i: range(0,n)) pos[a[i]].push_back(i);
    int ans=0;
    for (const auto& [u,v]: pos) ans=max(ans,(int)size(v));
    auto work=[&](vector<int> a, vector<int> b) {
        vector<int> pos;
        auto ia=begin(a), ib=begin(b);
        while (ia!=end(a)&&ib!=end(b)) {
            if (*ia<*ib) pos.push_back(1), ia++;
            else pos.push_back(0), ib++;
        }
        while (ia!=end(a)) pos.push_back(1), ia++;
        while (ib!=end(b)) pos.push_back(0), ib++;
        int n=size(pos); pos.insert(begin(pos),0);
        vector<int> pre1(n+1), pre0(n+1);
        for (int i=1; i<=n; ++i) {
            pre1[i]=pre1[i-1]+(pos[i]==1);
            pre0[i]=pre0[i-1]+(pos[i]==0);
        }
        int mx=-1e18, ans=0;
        for (int i=1; i<=n; ++i) {
            chmax(mx,pre1[i-1]-pre0[i-1]);
            chmax(ans,pre1[n]-pre1[i]+pre0[i]+mx);
        }
        return ans;
    };
    for (const auto& [u,v]: pos) if (pos.contains(u+k)) ans=max(ans,work(pos[u+k],pos[u]));
    cout<<ans<<'\n';

    
}