#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> p11;
typedef pair<string, int> ps1;
typedef pair<ll, ll> p1111;
#define vv vector
#define pb emplace_back
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define fi first
#define se second
#define endl '\n'
#define Endl '\n'
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define per(a, b, c) for(int a = b; a <= c; a ++)
#define aper(A) for(auto i : A) cout << i << ' ';cout << '\n'
#define lowbit(x) ((x) & (-x))
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define PAI acos(-1)
using ll = long long;
// #define double long double 
void umin(int &x,int y){if(x>y)x=y;}
void umax(int &x,int y){if(x<y)x=y;}
const int mod = 1e9 + 7;
void add(int &x, int y){x = (x + y) % mod;}
void pre_work(){}

void solve()
{
    int n, k;
    cin >> n >> k;
    vv<int> a(n + 1);
    for(int i = 1; i <= n; i ++)
    {
        cin >> a[i];
        a[i] -= i;
    }
    int l = 1, r = 1;
    multiset<int> s1, s2; // s1大于中位数, s2小于中位数
    int sum1 = 0, sum2 = 0;
    int ans = 0;
    function<void()> balance = [&]()
    {
        int sz1 = s1.size(), sz2 = s2.size();
        if(sz2 > sz1 + 1)
        {
            int now = *s2.begin();
            s1.insert(now);
            sum1 += now;
            sum2 -= now;
            s2.erase(s2.begin());
        }
        else if(sz1 > sz2)
        {
            int now = *s1.rbegin();
            s2.insert(now);
            sum2 += now;
            sum1 -= now;
            s1.erase(prev(s1.end()));
        }
    };
    function<void(int)> insert = [&](int x)
    {
        if(s2.empty()) s2.insert(x), sum2 += x;  
        else 
        {
            int num = *s2.begin();
            if(x >= num)
            {
                s2.insert(x);
                sum2 += x;
            }
            else 
            {
                s1.insert(x);
                sum1 += x;
            }
        }
        balance();
    };
    auto cal = [&]()
    {
        int sz = s1.size() + s2.size();
        if(sz & 1) return *s2.begin();
        else return (*s1.rbegin() + *s2.begin()) / 2;
    };
    auto check = [&]()
    {
        int mid = cal();
        int t = mid * s1.size() - sum1 + sum2 - mid * s2.size();
        if(t > k) return true;
        return false;
    };
    auto erase = [&](int x) ->void
    {
        if(s1.find(x) != s1.end()) s1.erase(s1.find(x)), sum1 -= x;
        else s2.erase(s2.find(x)), sum2 -= x;
        balance();
    };
    for(l = 1, r = 1; r <= n; r ++)
    {
        insert(a[r]);
        while(l <= r && check())
        {
            erase(a[l]);
            l ++;
        }
        umax(ans, s1.size() + s2.size());
    }
    cout << ans << endl;
}

signed main()
{
 	IOS;
	int tt = 1;
	cin >> tt;
	pre_work();
	while(tt --)
	{
		solve();
	}
	return 0;
}