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//          
//          
//           //     //    ////////     /\     /////////
//           //     //   //      //          //       //
//            ////////   //      //    //    //       //
//                  //   //      //    //    //       //
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#pragma GCC optimize(2)
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <cstring>
#include <cmath>
#include <list>
#include <stack>
#include <array>
#include <unordered_map>
#include <unordered_set>
#include <bitset>
#include <random>
#include <numeric>
#include <functional>
//#include <Windows.h>

using namespace std;

#define fa(i,op,n) for (int i = op; i <= n; i++)
#define fb(j,op,n) for (int j = op; j >= n; j--)
#define pb push_back
#define HashMap unordered_map
#define HashSet unordered_set
#define var auto
#define all(i) i.begin(), i.end()
#define endl '\n'
#define px first
#define py second
#define DEBUG(a) cout<<a<<endl

using VI = vector<int>;
using VL = vector<long long>;
using ll = long long;
using ull = unsigned long long;
using db = double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

template<class T1, class T2>
ostream& operator<<(ostream& out, const pair<T1, T2>& p) {
	out << '(' << p.first << ", " << p.second << ')';
	return out;
}

template<typename T>
ostream& operator<<(ostream& out, const vector<T>& ve) {
	for (T i : ve)
		out << i << ' ';
	return out;
}

template<class T1, class T2>
ostream& operator<<(ostream& out, const map<T1, T2>& mp) {
	for (auto i : mp)
		out << i << '\n';
	return out;
}

const int INF = 0x3f3f3f3f;
const ll LNF = 0x3f3f3f3f3f3f3f3f;
const int IINF = 0x7fffffff;
const int iinf = 0x80000000;
const ll LINF = 0x7FFFFFFFFFFFFFFF;
const ll linf = 0x8000000000000000;
int dx[8] = { 1, -1, 0, 0, 1, -1, 1, -1 };
int dy[8] = { 0, 0, 1, -1, 1, -1, -1, 1 };

//#include "Lynia.h"

const int mod = 998244353;
const int N = 1e6 + 10;

void solve(int CASE)
{
	ll n, k; cin >> n >> k;
	var a = vector<ll>(n + 1, 0);
	fa(i, 1, n)cin >> a[i], a[i] -= i;

	multiset<ll>r;
	multiset<ll, greater<ll>>l;
	ll l_sum = 0, r_sum = 0;

	var f = [&](int len)->void {
		ll tmp;
		while (l.size() and r.size() and (*l.begin()) > (*r.begin())) {
			tmp = (*l.begin());
			r_sum += tmp, r.insert(tmp);
			l_sum -= tmp, l.erase(l.begin());
		}
		if (len & 1) {
			while (l.size() < r.size() + 1) {
				tmp = (*r.begin());
				l_sum += tmp, l.insert(tmp);
				r_sum -= tmp, r.erase(r.begin());
			}
			while (l.size() > r.size() + 1) {
				tmp = (*l.begin());
				r_sum += tmp, r.insert(tmp);
				l_sum -= tmp, l.erase(l.begin());
			}
		}
		else {
			while (l.size() < r.size()) {
				tmp = (*r.begin());
				l_sum += tmp, l.insert(tmp);
				r_sum -= tmp, r.erase(r.begin());
			}
			while (l.size() > r.size()) {
				tmp = (*l.begin());
				r_sum += tmp, r.insert(tmp);
				l_sum -= tmp, l.erase(l.begin());
			}
		}
		};

	ll j = 1;
	ll ans = 1;
	fa(i, 1, n) {
		if (l.size() == 0)l_sum += a[i], l.insert(a[i]);
		else {
			if (a[i] <= (*l.begin()))l_sum += a[i], l.insert(a[i]);
			else r_sum += a[i], r.insert(a[i]);
		}

		f(i - j + 1);
		ll mmid = (*l.begin());
		ll now = (mmid * (ll)l.size() - l_sum) + (r_sum - mmid * (ll)r.size());

		while (now > k and j < i) {
			if (l.count(a[j])) l_sum -= a[j], l.erase(l.find(a[j]));
			else r_sum -= a[j], r.erase(r.find(a[j]));
			j++;

			f(i - j + 1); // 刷新双set
			mmid = (*l.begin()); // 中位数
			now = (mmid * (ll)l.size() - l_sum) + (r_sum - mmid * (ll)r.size());
		}

		ans = max(ans, i - j + 1);
	}
	cout << ans << endl;
	return;
}

int main()
{
	//SetConsoleOutputCP(CP_UTF8);
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	int _ = 1;
	cin >> _;
	fa(i, 1, _)solve(i);
	return 0;
}