#pragma GCC optimize(3)
#pragma GCC target("avx")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<unordered_map>
#include<vector>
#include<queue>
using namespace std;
#define int long long 
#define endl '\n'
const int N = 4e6 + 10;
vector<int>m[N];
vector<int>d[N];
vector<int>tt;
int b = 2e6;
int a[N];
int n, k;
void solve()
{
	cin >> n >> k;
	for (int i = 0; i < n; i++)
	{
		int x;
		cin >> x;
		if(!a[x+b]) tt.emplace_back(x+b);
		a[x + b]++;
		m[x+b].emplace_back(a[x + b] - a[x + b + k]);
		m[x - k+b].emplace_back(a[x + b - k] - a[x + b]);

	}
	for (auto c:tt)
	{
		for (int i = 0; i < m[c].size(); i++)
		{
			if (!i) d[c].emplace_back(m[c][i]);
			else d[c].emplace_back(m[c][i] - m[c][i - 1]);
		}
	}
	vector<int>f;
	int res = 0;
	for (auto c : tt)
	{
		f.clear();
		for (int i = 0; i < d[c].size(); i++)
		{
			if (!i) f.emplace_back(d[c][i]);
			else f.emplace_back(max(f.back() + d[c][i], d[c][i]));
			res = max(res, f[i] + a[c+k]);
		}
	}
	cout << res << endl;
}
signed main()
{
	std::ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int T = 1;
	//cin >> T;
	while (T--)
	{
		solve();
	}
	return 0;
}

answer.code:22:39: warning: bad option ‘-fwhole-program’ to pragma ‘optimize’ [-Wpragmas]
   22 | #pragma GCC optimize("-fwhole-program")
      |                                       ^
answer.code:29:41: warning: bad option ‘-fstrict-overflow’ to pragma ‘optimize’ [-Wpragmas]
   29 | #pragma GCC optimize("-fstrict-overflow")
      |                                         ^
answer.code:31:41: warning: bad option ‘-fcse-skip-blocks’ to pragma ‘optimize’ [-Wpragmas]
   31 | #pragma GCC optimize("-fcse-skip-blocks")
      |                                         ^
answer.code:45:51: warning: bad option ‘-funsafe-loop-optimizations’ to pragma ‘optimize’ [-Wpragmas]
   45 | #pragma GCC optimize("-funsafe-loop-optimizations")
      |                                                   ^
answer.code:65:12: warning: bad option ‘-fwhole-program’ to attribute ‘optimize’ [-Wattributes]
   65 | void solve()
      |            ^
answer.code:65:12: warning: bad option ‘-fstrict-overflow’ to attribute ‘optimize’ [-Wattributes]
answer.code:65:12: warning: bad option ‘-fcse-skip-blocks’ to attribute ‘optimize’ [-Wattributes]
answer.code:65:12: warning: bad option ‘-funsafe-loop-optimizations’ to attribute ‘optimize’ [-Wattributes]
answer.code:100:13: warning: bad option ‘-fwhole-program’ to attribute ‘optimize’ [-Wattributes]
  100 | signed main()
      |             ^
answer.code:100:13: warning: bad option ‘-fstrict-overflow’ to attribute ‘optimize’ [-Wattributes]
answer.code:100:13: warning: bad option ‘-fcse-skip-blocks’ to attribute ‘optimize’ [-Wattributes]
answer.code:100:13: warning: bad option ‘-funsafe-loop-optimizations’ to attribute ‘optimize’ [-Wattributes]
In file included from /usr/include/c++/13/string:43,
                 from /usr/include/c++/13/bits/locale_classes.h:40,
                 from /usr/include/c++/13/bits/ios_base.h:41,
                 from /usr/include/c++/13/ios:44,
                 from /usr/include/c++/13/ostream:40,
                 from /usr/include/c++/13/iostream:41,
                 from answer.code:48:
/usr/include/c++/13/bits/allocator.h: In destructor ‘constexpr std::_Vector_base<long long int, std::allocator<long long int> >::_Vector_impl::~_Vector_impl()’:
/usr/include/c++/13/bits/allocator.h:184:7: error: inlining failed in call to ‘always_inline’ ‘constexpr std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = long long int]’: target specific option mismatch
  184 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from /usr/include/c++/13/vector:66,
                 from answer.code:53:
/usr/include/c++/13/bits/stl_vector.h:133:14: note: called from here
  133 |       struct _Vector_impl
      |              ^~~~~~~~~~~~