#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int mod = 1e9 + 7, inf = 0x3f3f3f3f;


bool chmax(int &a, int b) {
	if (a < b) {
		a = b;
		return 1;
	} 
	return 0;
};

void solve() {
	int n, k;
	cin >> n >> k;
	vector<int> a(n);
	for (int i = 0; i < n; i ++) {
		cin >> a[i];
		a[i] = a[i] - i;
	}
	multiset<int> s1, s2;

	s1.insert(-inf);
	s2.insert(inf);
	ll sum1 = 0, sum2 = 0;

	auto adj = [&]() -> void {
		while (s1.size() > s2.size() + 1) {
			auto it = (-- s1.end());
			int x = *it;
			s2.insert(x);
			s1.erase(it);

			sum1 = sum1 - x;
			sum2 = sum2 + x;

		}
		while(s2.size() > s1.size()) {
			auto it = s2.begin();
			int x = *it;
			s1.insert(x);
			s2.erase(it);
			sum2 = sum2 - x;
			sum1 = sum1 + x;
		}
	};

	auto add = [&](int x) -> void {
		if (x < *s2.begin()) {
			s1.insert(x);
			sum1 = sum1 + x;
		} else {
			s2.insert(x);
			sum2 = sum2 + x;
		}
		adj();
	};


	auto del = [&](int x) -> void {
		auto it = s1.lower_bound(x);
		if (it != s1.end()) {
			sum1 = sum1 - x;
			s1.erase(it);

		} else {
			it = s2.lower_bound(x);
			sum2 = sum2 - x;
			s2.erase(it);
		}
		adj();
	};
	int ans = 0;
	for (int i = 0, j = 0; i < n; i ++) {
		add(a[i]);
		auto it = (--s1.end());
		ll adv = *it;
		ll need = adv * s1.size() - sum1 + sum2 - adv * s2.size();
		while (need > k) {
			del(a[j ++]);
			it = (--s1.end());
			adv = (*it);
			need = adv * s1.size() - sum1 + sum2 - adv * s2.size();
		}
		chmax(ans, s1.size() + s2.size() - 2);
	}
	cout << ans << '\n';
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	int t;
	cin >> t;
	while (t --) {
		solve();
	}
	return 0;
}