#include<bits/stdc++.h>
using namespace std;
#define fast ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define int long long
int n,m;
const int N=2e6+7;
int a[N];
multiset<int> s1,s2;
int sum1,sum2;
void clear(){
    while(s1.size()>s2.size()+1){
        int x=*s1.rbegin();
        s2.insert(x);
        sum2+=x,sum1-=x;//一定要更新这两个
        s1.erase(s1.find(x));
    }
    while(s1.size()<s2.size()){
        int x=*s2.begin();
        s1.insert(x);
        sum1+=x,sum2-=x;
        s2.erase(s2.find(x));
    }
    while(s2.size()&&(*s1.rbegin())>(*s2.begin())){
        int x=(*s1.rbegin()),y=(*s2.begin());//注意multiset的最后一个是rbegin
        s2.insert(x),s1.insert(y);
        s2.erase(s2.find(y)),s1.erase(s1.find(x));
        sum1-=x,sum2-=y;
        sum1+=y,sum2+=x;
    }
}
int cal(){
    //注意我们这里维护的中位数是*s1.rbegin(),参照上面的s2.size()大于s1.size()才更新
    int res=(s1.size()*(*s1.rbegin())-sum1)+(sum2-s2.size()*(*s1.rbegin()));
    return res;
}
void solve(){
    s1.clear();
    s2.clear();
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
        a[i]=a[i]-i;
    }
    s1.insert(a[1]);
    sum1=a[1];
    sum2=0;
    int ans=1;
    for(int i=2,j=1;i<=n;i++){
        s1.insert(a[i]),sum1+=a[i];
        clear();
        while(j<=n&&cal()>m){
            if(s2.count(a[j])) s2.erase(s2.find(a[j])),sum2-=a[j];
            else s1.erase(s1.find(a[j])),sum1-=a[j];
            j++;
            clear();
        }
        clear();
        ans=max(ans,(int)s1.size()+(int)s2.size());
    }
    cout<<ans<<endl;
}
signed main(){
    fast;
    int t=1;
    cin>>t;
    while(t--){
        solve();
    }
}