#include <bits/stdc++.h>

#define OobugoO_IOS std::ios::sync_with_stdio(false),std::cin.tie(nullptr)
#define x first
#define y second
#define pii pair<int,int>
#define pll pair<long long,long long>

typedef long long ll;
typedef long double LD;

//using namespace std;

const int mod = 1e9 + 7;
const int N = 100010;
const int M = 1010;
const LD eps=1e-8;

void solve(){
    int n,k;  std::cin>>n>>k;
    std::vector<ll> a(n);
    for(int i=0;i<n;i++){
        std::cin>>a[i]; a[i]-=i;
    }
    int l=0,r=0;
    std::multiset<ll> s1,s2;
    ll sum1=0,sum2=0;
    auto keep_bal=[&](){
        while(s2.size()<s1.size()){
            s2.insert(*s1.rbegin());
            sum2+=*s1.rbegin();
            sum1-=*s1.rbegin();
            s1.erase(s1.find(*s1.rbegin()));
        }
        while(s1.size()<s2.size()){
            s1.insert(*s2.begin());
            sum1+=*s2.begin();
            sum2-=*s2.begin();
            s2.erase(s2.begin());
        }
    };
    s1.insert(a[0]); sum1+=a[0];
    int ans=1;
    while(r<n){
        keep_bal();
        ll num=*s1.rbegin();
        ll ret=(num*s1.size()-sum1)+(sum2-num*s2.size());
        if(ret>k){
            if(a[l]<=num){
                sum1-=a[l];
                s1.erase(s1.find(a[l]));
            }else{
                sum2-=a[l];
                s2.erase(s2.find(a[l]));
            }
            l++;
        }else{
            ans=std::max(ans,r-l+1);
            r++;
            if(r==n)    break;
            if(a[r]>=num){
                s2.insert(a[r]);
                sum2+=a[r];
            }else{
                s1.insert(a[r]);
                sum1+=a[r];
            }
        }
        if(l>r) r++;
    }
    std::cout<<ans<<"\n";
}

signed main(){

#ifdef Onlion_Judge
    freopen("IO/input.in", "r", stdin);
    freopen("IO/output.out", "w", stdout);
#endif

    OobugoO_IOS;
    int t = 1;  std::cin>>t;
    while (t--)
        solve();
    return 0;
}