#include<bits/stdc++.h> 
#define ll long long
using namespace std;
#define endl '\n'
const int N = 5e5 + 5;
ll a[N];
ll n, k;
void solve()
{
    cin >> n >> k;
    for (int i = 1;i <= n;i++) {
        cin >> a[i];
        a[i] -= i;
    }
    ll l = 1, r = 1;
    ll ans = 1;
    multiset<ll>s1, s2;
    ll num = 0;
    ll cnt = 0;
    ll sum1 = 0, sum2 = 0;
    sum2 += a[1], s2.insert(a[1]);
    while (r <= n) {
        int mid = *s2.begin(), sz1 = s1.size(), sz2 = s2.size();
        int tmp = (mid * sz1 - sum1) + (sum2 - sz2 * mid);
        if (tmp <= k) {
            ans = max(r - l + 1, ans), r++;
            if (r == n + 1)
                break;
            if (a[r] <= mid)
                s1.insert(a[r]), sum1 += a[r];
            else
                s2.insert(a[r]), sum2 += a[r];
        }
        else {
            if (s1.find(a[l]) != s1.end())
                s1.erase(s1.find(a[l])), sum1 -= a[l];
            else
                s2.erase(s2.find(a[l])), sum2 -= a[l];
            l++;
        }
        if (s2.size() > s1.size() + 1) {
            s1.insert(*s2.begin()), sum1 += *s2.begin();
            sum2 -= *s2.begin(), s2.erase(s2.begin());
        }
        else if (s2.size() < s1.size()) {
            int num = *(--s1.end());
            s2.insert(num), sum2 += num;
            s1.erase(s1.find(num)), sum1 -= num;
        }
    }
    cout << ans << endl;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}