#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using i64 = long long;
using namespace std;
const int N = 1e6 + 5;
// const int B = 340;
// const int M = 5e3 + 5;
// const int base = 1753591;
// const int mod = 998244353;
const int mod = 1e9 + 7;
// const double pi = acos(-1);

int n, a[N];
i64 lim;
struct node
{
    i64 sum;
    int l, r, siz;
    node operator+(node tmp)
    {
        node res;
        res.sum = sum + tmp.sum;
        res.siz = siz + tmp.siz;
        return res;
    }
} st[N << 2];
#define lc st[cur].l
#define rc st[cur].r
int tot, root;
void pushup(int cur)
{
    st[cur].sum = st[lc].sum + st[rc].sum;
    st[cur].siz = st[lc].siz + st[rc].siz;
}
void insert(int &cur, int l, int r, int p, int x)
{
    if (!cur)
        cur = ++tot;
    if (l == r)
    {
        st[cur].sum += p * x;
        st[cur].siz += x;
        return;
    }
    int mid = l + r >> 1;
    if (p <= mid)
        insert(lc, l, mid, p, x);
    else
        insert(rc, mid + 1, r, p, x);
    pushup(cur);
}
node query(int cur, int l, int r, int a, int b)
{
    if (a <= l && r <= b)
        return st[cur];
    int mid = l + r >> 1;
    node res = {0, 0, 0, 0};
    if (a <= mid)
        res = res + query(lc, l, mid, a, b);
    if (b > mid)
        res = res + query(rc, mid + 1, r, a, b);
    return res;
}
const int L = -1e6, R = 1e9 + 1e6;
void solve()
{
    cin >> n >> lim;
    tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update> s;
    for (int i = 1; i <= n; i++)
        cin >> a[i], a[i] -= i;
    int ans = 1;
    s.insert({a[1], 1});
    insert(root, L, R, a[1], 1);
    int l = 0, r = 0;
    for (int i = 2, pre = 1; i <= n; i++)
    {
        insert(root, L, R, a[i], 1);
        s.insert({a[i], i});
        int k = (i - pre) / 2;
        auto mid = s.find_by_order(k);
        i64 sum = 0;
        auto t1 = query(root, L, R, L, mid->first - 1);
        auto t2 = query(root, L, R, mid->first + 1, R);
        sum = (i64)(mid->first) * t1.siz - t1.sum + t2.sum - (i64)(mid->first) * t2.siz;
        while (1)
        {
            if (sum > lim)
            {
                insert(root, L, R, a[pre], -1);
                s.erase({a[pre], pre});
                k = (i - pre) / 2;
                mid = s.find_by_order(k);
                auto t1 = query(root, L, R, L, mid->first - 1);
                auto t2 = query(root, L, R, mid->first + 1, R);
                sum = (i64)(mid->first) * t1.siz - t1.sum + t2.sum - (i64)(mid->first) * t2.siz;
                pre++;
            }
            else
                break;
        }
        ans = max(ans, i - pre + 1);
    }
    cout << ans << '\n';
    for (int i = 0; i <= tot; i++)
        st[i] = {0, 0, 0, 0};
    root = tot = 0;
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    cin >> t;
    cout << fixed << setprecision(10);
    while (t--)
        solve();
}