#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <vector>

using namespace std;

// BEGIN NO SAD
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
typedef vector<int> vi;
#define f first
#define s second
#define derr if(1) cerr

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
 
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << flush;
// END NO SAD

template<class Fun>
class y_combinator_result {
  Fun fun_;
public:
  template<class T>
  explicit y_combinator_result(T &&fun): fun_(std::forward<T>(fun)) {}

  template<class ...Args>
  decltype(auto) operator()(Args &&...args) {
    return fun_(std::ref(*this), std::forward<Args>(args)...);
  }
};

template<class Fun>
decltype(auto) y_combinator(Fun &&fun) {
  return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
}

template<class T>
bool updmin(T& a, T b) {
  if(b < a) {
    a = b;
    return true;
  }
  return false;
}
template<class T>
bool updmax(T& a, T b) {
  if(b > a) {
    a = b;
    return true;
  }
  return false;
}
typedef int64_t ll;

struct koosaga {
  multiset<ll> big, small;
  ll bigs, smalls;
  koosaga() {
    bigs = 0;
    smalls = 0;
  }
  ll qry() {
    // debug(small, big);
    ll median = *big.begin();
    return (bigs - median * sz(big)) + (sz(small) * median - smalls);
  }
  void _rebalance() {
    while(sz(small) > sz(big)) {
      ll biggest = *small.rbegin();
      small.erase(small.find(biggest));
      smalls -= biggest;
      big.insert(biggest);
      bigs += biggest;
    }
    while(sz(big) - sz(small) >= 2) {
      ll smallest = *big.begin();
      big.erase(big.find(smallest));
      bigs -= smallest;
      small.insert(smallest);
      smalls += smallest;
    }
    while(sz(small) && sz(big) && *small.rbegin() > *big.begin()) {
      ll biggest = *big.begin();
      big.erase(big.find(biggest));
      bigs -= biggest;
      small.insert(biggest);
      smalls += biggest;
      biggest = *small.rbegin();
      small.erase(small.find(biggest));
      smalls -= biggest;
      big.insert(biggest);
      bigs += biggest;
    }
  }
  void ins(ll x) {
    smalls += x;
    small.insert(x);
    _rebalance();
  }
  void erase(ll x) {
    if(big.find(x) != big.end()) {
      big.erase(big.find(x));
      bigs -= x;
    }
    else {
      assert(small.find(x) != small.end());
      small.erase(small.find(x));
      smalls -= x;
    }
    _rebalance();
  }
};

void rsolve() {
  int n;
  ll k;
  cin >> n >> k;
  vector<ll> v(n);
  for(int i = 0; i < n; i++) {
    cin >> v[i];
    v[i] -= i;
  }
  // debug(v);
  int ret = 0;
  koosaga koo;
  int lhs = 0;
  for(int i = 0; i < n; i++) {
    koo.ins(v[i]);
    while(koo.qry() > k) {
      // debug(lhs, i, koo.qry());
      koo.erase(v[lhs++]);
    }
    updmax(ret, i-lhs+1);
  }
  cout << ret << "\n";
}
void solve() {
  int t;
  cin >> t;
  while(t--) rsolve();
}

// what would chika do
// are there edge cases (N=1?)
// are array sizes proper (scaled by proper constant, for example 2* for koosaga tree)
// integer overflow?
// DS reset properly between test cases
// are you doing geometry in floating points
// are you not using modint when you should

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
}