#include<iostream>
#include<cstring>
#include<stdlib.h>
#include<unordered_map>
#include<vector>
#include<array>
#include<math.h>
#include<map>
#include<stdio.h>
#include<queue>
#include<assert.h>
#include<string>
#include<limits.h>
#include<stack>
#include<set>
#include<list>
#include<algorithm>
#include <chrono>
#include<random>
using namespace std;

typedef long long LL;
#define int long long
typedef unsigned long long ULL;
typedef pair<LL, LL>PII;
typedef pair<double, double>PDD;
typedef pair<char, char>PCC;
LL n, m, k;

const LL inf = 1e18;
const LL N = 1e6 + 10;
const LL mod = 1e9 + 7;
const LL mod2 = 998244353;


void solve() {
    cin >> n >> k;
    vector<int>a(n + 1);
    for (int i = 1;i <= n;i++) {
        cin >> a[i];
        a[i] -= i;
    }
    multiset<int>p, q;
    int s1 = 0, s2 = 0,ans = 1;
    auto balance = [&]()->void {
        while (q.size() > p.size() + 1) {
            p.insert(*(q.begin()));
            s2 -= *(q.begin());
            s1 += *(q.begin());
            q.erase(q.find(*(q.begin())));
        }
        while (p.size() > q.size()) {
            q.insert(*(p.begin()));
            s1 -= *(p.begin());
            s2 += *(p.begin());
            p.erase(p.find(*(p.begin())));
        }
    };
    auto cost = [&]()->int {
        int mid = *(q.begin());
        return (mid * p.size() - s1) + (s2 - mid * q.size());
    };
    for (int i = 1,l=  1;i <= n;i++) {
        if (q.size() == 0) {
            q.insert(a[i]);
            s2 += a[i];
        }
        else {
            if (a[i] >= *(q.begin())) {
                q.insert(a[i]);
                s2 += a[i];
            }
            else {
                p.insert(a[i]);
                s1 += a[i];
            }
        }
        balance();
        while (l<i && cost()>k) {
            if (p.size()&&p.find(a[l]) != p.end()) {
                p.erase(p.find(a[l]));
                s1 -= a[l];
            }
            else {
                s2 -= a[l];
                q.erase(q.find(a[l]));
            }
            balance();
            l++;
        }
        ans = max(ans, i - l + 1);
    }
    cout << ans << "\n";
}
signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}