#include <bits/stdc++.h>

#define x first
#define y second
#define el '\n'
#define debug(x) cerr << #x << ": " << x << endl
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int N = 3e5 + 10, INF = 0x3f3f3f3f, mod = 998244353;

void solve() {
    int n; ll k; cin >> n >> k;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) cin >> a[i], a[i] -= i;
    int ans = 1;
	ll s1 = 0, s2 = 0;
	multiset<ll> Q1, Q2;
	for (int i = 0, j = 0; i < n; ++i) {
		if (Q1.empty() || a[i] >= *Q1.begin()) Q1.insert(a[i]), s1 += a[i];
		else Q2.insert(a[i]), s2 += a[i];
		while (Q1.size() >= Q2.size() + 2) {
			s1 -= *Q1.begin(), s2 += *Q1.begin();
			Q2.insert(*Q1.begin()), Q1.erase(Q1.begin());
		}
		while (Q1.size() < Q2.size()) {
			s2 -= *Q2.rbegin(), s1 += *Q2.rbegin();
			Q1.insert(*Q2.rbegin()), Q2.erase(Q2.find(*Q2.rbegin()));
		}
		// cout << j << ' ' << i << el;
		// cout << s1 << ' ' << s2 << el;
		// cout << *Q1.begin() << el;
		while (j && s1 - Q1.size() * *Q1.begin() + Q2.size() * *Q1.begin() - s2 <= k) {
			ans = max(ans, i - j + 1);
			--j;
			if (Q1.empty() || a[j] >= *Q1.begin()) Q1.insert(a[j]), s1 += a[j];
			else Q2.insert(a[j]), s2 += a[j];
			while (Q1.size() >= Q2.size() + 2) {
				s1 -= *Q1.begin(), s2 += *Q1.begin();
				Q2.insert(*Q1.begin()), Q1.erase(Q1.begin());
			}
			while (Q1.size() < Q2.size()) {
				s2 -= *Q2.rbegin(), s1 += *Q2.rbegin();
				Q1.insert(*Q2.rbegin()), Q2.erase(Q2.find(*Q2.rbegin()));
			}
			if (s1 - Q1.size() * *Q1.begin() + Q2.size() * *Q1.begin() - s2 <= k) ans = max(ans, i - j + 1);
		}
		if (Q1.count(a[j])) Q1.erase(Q1.find(a[j])), s1 -= a[j];
		else Q2.erase(Q2.find(a[j])), s2 -= a[j];
		while (Q1.size() >= Q2.size() + 2) {
			s1 -= *Q1.begin(), s2 += *Q1.begin();
			Q2.insert(*Q1.begin()), Q1.erase(Q1.begin());
		}
		while (Q1.size() < Q2.size()) {
			s2 -= *Q2.rbegin(), s1 += *Q2.rbegin();
			Q1.insert(*Q2.rbegin()), Q2.erase(Q2.find(*Q2.rbegin()));
		}
		++j;
	}
	cout << ans << el;
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int tcase = 1;
    cin >> tcase;
    while (tcase--) solve();
}