#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define mk make_pair
#define S second
#define F first
const int mil = 1e6;
int solve(vector<int> &v){
    int n = v.size();
    int sum = 0;
    for(auto it : v) sum += it;
    int sum2 = 0;
    int mx = 0;
    for(auto it : v){
        if(it == 0) sum2 ++;
        else sum2--;
        if(sum2 < 0) sum2 = 0;
        mx = max(mx, sum2);
    }
    return sum + mx;
}
int main(){
	int n, k;
	cin >> n >> k;
    vector<int> v[3 * mil + 5];
    int x;
    for(int i = 0; i < n; i++){
        cin >> x;
        v[x + mil].pb(i);
       // cout << x + mil << " " << i << endl;
    }
    int ans = 0;
    vector<int> vc;
    for(int i = 0; i <=2 * mil; i++){
        if(i - k < 0 || i - k > 2 * mil) ans = max(ans, int(v[i].size()));
        else {
            int l = 0, r = 0;
            vc.clear();
            while(l < v[i].size() || r < v[i - k].size()){
                 if(r == v[i - k].size()) vc.push_back(1), l++;
                 else if(l == v[i].size()) vc.push_back(0), r++;
                 else if(v[i][l] < v[i - k][r]) vc.push_back(1), l++;
                 else vc.push_back(0), r++;
               //  cout << vc.back() << " ";
                 if(vc.size() > n){
                    //  cout << "wtf\n";
                    //  cout << l << " " << r << endl;
                   //   cout << v[i].size() << " " << v[i - k].size() << endl;
                    //  break;
                 }
            }
            ans = max(ans, solve(vc));
        }
    }

    cout << ans << '\n';
}