#include <bits/stdc++.h>
#define int long long

#define x first
#define y second
#define pb push_back

using namespace std;

const int N = 2e5 + 10;
const int P = 1e9 + 7, INF = 0x3f3f3f3f;

typedef pair<int, int> PII;
typedef pair<double, double> PDD;
typedef long long LL;

int n, k;
int sum1, sum2;
multiset<int> s1;//升序
multiset<int, greater<int>> s2;//降序
int mid;

void bal() {
    if(s1.size() < s2.size()) {
        auto t = s2.begin();
        sum1 += *t, sum2 -= *t;
        s1.insert(*t);
        s2.erase(t);
    }
    if(s1.size() > s2.size() + 1) {
        auto t = s1.begin();
        sum1 -= *t, sum2 += *t;
        s2.insert(*t);
        s1.erase(t);
    }
    mid = *s1.begin();
}

void add(int x) {
    if(x > mid) s1.insert(x), sum1 += x;
    else s2.insert(x), sum2 += x;
    bal();
}

void del(int x) {
    if(s1.count(x)) s1.erase(s1.find(x)), sum1 -= x;
    else s2.erase(s2.find(x)), sum2 -= x;
    bal();
}

bool check() {
    return sum1 - s1.size() * mid + s2.size() * mid - sum2 <= k;
}

void solve() {
    cin >> n >> k;
    s1.clear(), s2.clear();
    sum1 = sum2 = 0;
    vector<int> a(n);
    for(int i = 0; i < n; i ++ ) cin >> a[i], a[i] -= i;
    //     cout << '\n';
    // for(int i = 0; i < n; i ++ ) cout << a[i] << ' ';
    //     cout << '\n';
    int res = 1;
    for(int r = 0, l = 0; r < n; r ++ ) {
        add(a[r]);
        if(!check()) del(a[l ++ ]);
        res = max(r - l + 1, res);
    }
    cout << res << '\n';
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int T = 1;
    cin >> T;
    while(T -- ) {
        solve();
    }
    return 0;
}