#pragma GCC optimize(3)
#include <bits/stdc++.h>
using namespace std;
//#define __LOCAL_DEBUG__
#ifdef __LOCAL_DEBUG__
#define _debug(fmt, ...) fprintf(stderr, "[%s %3d]: " fmt "\n", \
__func__, __LINE__, ##__VA_ARGS__)
#else
# define _debug(...) (void(0))
#endif
#define eb emplace_back
#define pb push_back
#define fi first
#define se second
#define rep(i,l,r) for (int i = l,_ = r;i< _;i++)
#define REP(i,l,r) for (int i=l,_=r;i<=_;i++)
#define leave(x) do {cout<<#x<<endl;fflush(stdout);return 0;}while (0);
#define untie do{ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);cout << fixed << setprecision(18);}while (0)
#define range(x) x.begin(),x.end()
typedef long long LL;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef unsigned int uint;
typedef unsigned long long  ull;
typedef __int128_t i128;
typedef __uint128_t u128;
const LL N = 5E5 + 10;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3fLL;
const int dx[8] = {-1, 0, 1, 0, -1, 1, 1, -1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const double eps = 1E-10;
const long double PI = 3.1415926535897932384l;
mt19937 wdy(time(0));
template<class T> 
bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> 
bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; }
template<class T> 
void printv(const T& con) { for (auto& i : con) cout << i << ' '; cout << endl;}
/************* header ******************/



LL a[N];
multiset<LL> s1, s2;
LL sum1 = 0, sum2 = 0;


void adjust() {
    while (s2.size() > s1.size()) {
        s1.insert(*s2.begin());
        sum1 += (*s2.begin());
        sum2 -= (*s2.begin());
        s2.erase(s2.begin());
    }

    while (s2.size() + 1 < s1.size()) {
        auto it = (--s1.end());
        sum1 -= (*it);
        sum2 += (*it);
        s2.insert(*it);
        s1.erase(it);
    }
}


void add(LL x) {
    if (x < *s2.begin()) {
        sum1 += x;
        s1.insert(x);
    } else {
        sum2 += x;
        s2.insert(x);
    }
    adjust();
}


void del(LL x) {
    auto it = s1.find(x);
    if (it != s1.end()) {
        sum1 -= x;
        s1.erase(it);
    } else {
        sum2 -= x;
        s2.erase(s2.find(x));
    }
    adjust();
}

void solve() {
    LL n, k;
    cin >> n >> k;
    s1.clear();
    s2.clear();
    sum1 = 0, sum2 = 0;
    s1.insert(-INF);
    s2.insert(INF);
    for (int i = 1; i <= n; i ++) {
        cin >> a[i];
        a[i] -= i;
    }
    LL ans = 0;
    
    for (int i = 1, j = 1; i <= n; i ++) {
        add(a[i]);
        auto it = (--s1.end());
        LL need, x, siz1, siz2;
        x = (*it), siz1 = s1.size(), siz2 = s2.size();
        need = siz1 * x - sum1 + sum2 - siz2 * x;
        while (need > k) {
            del(a[j ++]);
            it = (--s1.end());
            x = (*it), siz1 = s1.size(), siz2 = s2.size();
            need = siz1 * x - sum1 + sum2 - siz2 * x;
        }
        ans = max(siz1 + siz2 - 2, ans);
    }

    cout << ans << '\n';
}


int main() {
    untie;
    int T = 1; cin >> T;
    while (T --) {
        solve();
    }
    return 0;
}