#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll t;

void solve(){
	ll n,k;
	cin>>n>>k;
	vector<ll>a(n+10);
	for(ll i=1;i<=n;i++)
		cin>>a[i],a[i]-=i;
	ll ans=1,len=1,l=1,r=1;
	multiset<ll>s1,s2;
	s2.insert(a[1]);
	ll sum1=0;
	ll sum2=a[1];
	while(l<=n)
	{
		ll mid=*s2.begin();
		ll res=mid*s1.size()-sum1+sum2-mid*s2.size();
		if(res<=k)
		{
			ll si=s1.size()+s2.size();
			ans=max(ans,si);
			l++;
			s2.insert(a[l]);
			sum2+=a[l];
			if(s2.size()>s1.size()+1)
			{
				ll ss=*s2.begin();
				s1.insert(*s2.begin());
				s2.erase(*s2.begin());
				sum2-=ss;
				sum1+=ss;
			}
		}
		else{
			if(a[r]>=*s2.begin())
			{
				s2.erase(a[r]);
				r++;
				sum2-=a[r];
			}
			else{
				s1.erase(a[r]);
				r++;
				sum1-=a[r];
			}
			if(s2.size()>s1.size()+1)
			{
				ll ss=*s2.begin();
				s1.insert(*s2.begin());
				s2.erase(*s2.begin());
				sum2-=ss;
				sum1+=ss;
			}
		}
	}
	cout<<ans<<endl;
}

int main()
{
	cin>>t;
	while(t--)
	{
		solve();
	}
}