#include<bits/stdc++.h>
#define rep(i,j,k) for (int i=(j);i<=(k);++i)
#define dep(i,j,k) for (int i=(j);i>=(k);--i)
#define MAXN 100000
using namespace std;
typedef long long LL;

multiset<int> dwn,up;
LL sumup,sumdwn;
int a[MAXN+5];

void flat() {
    if (up.size()>dwn.size()+1) {
        auto it=up.begin();
        sumup-=*it;
        sumdwn+=*it;
        dwn.insert(*it);
        up.erase(it);
    } else if (up.size()<dwn.size()) {
        auto it=--dwn.end();
        sumdwn-=*it;
        sumup+=*it;
        up.insert(*it);
        dwn.erase(it);
    }
}

void add(int x) {
    if (up.empty()||x>=*up.begin()) {
        up.insert(x);
        sumup+=x;
    } else {
        dwn.insert(x);
        sumdwn+=x;
    }
    flat();
}

void del(int x) {
    if (!up.empty()&&x>=*up.begin()) {
        up.erase(x);
        sumup-=x;
    } else {
        dwn.erase(x);
        sumdwn-=x;
    }
    flat();
}

LL k;
inline bool check() {
    return k>=sumup-(*up.begin())*up.size()+(*up.begin())*dwn.size()-sumdwn;
}

void solve() {
    int n;
    cin>>n>>k;
    sumup=sumdwn=0;
    up.clear(),dwn.clear();
    rep(i,1,n) cin>>a[i];
    rep(i,1,n) a[i]-=i;
    int l=1,ans=1;
    rep(r,1,n) {
        add(a[r]);
        while (l<r&&!check()) del(a[l++]);
        ans=max(ans,r-l+1);
    }
    cout<<ans<<"\n";
}

int main() {
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int t;
    cin>>t;
    while (t--) solve();
    return 0;
}