#include<bits/stdc++.h>
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define pre(i,a,n) for(int i=n;i>=a;i--)
#define ls(x) lson[(x)]
#define rs(x) rson[(x)]
#define IOS ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
using ll=long long;
#define N int(5e5+10)
int rt,a[N],lson[N<<2],rson[N<<2],sz[N<<2],cnt;
ll sum[N<<2],b[N];
int build(int cl,int cr)
{
	int n1=cnt++;
	if(cl<cr)
	{
		int mid=(cl+cr)>>1;
		ls(n1)=build(cl,mid);
		rs(n1)=build(mid+1,cr);
	}
	return n1;
}
void modify(int n1,int cl,int cr,int pos,int x)
{
	if(cl==cr)
	{
		sz[n1]+=x,sum[n1]+=1ll*x*b[cl];
		return;	
	}
	int mid=(cl+cr)>>1;
	if(pos<=mid) modify(ls(n1),cl,mid,pos,x);
	else modify(rs(n1),mid+1,cr,pos,x);
	sz[n1]=sz[ls(n1)]+sz[rs(n1)];
	sum[n1]=sum[ls(n1)]+sum[rs(n1)];
}
ll que(int n1,int cl,int cr,int ki,int tp)
{
	if(cl==cr) return (tp?(1ll*ki*b[cl]):b[cl]);
	int mid=(cl+cr)>>1;
	if(sz[ls(n1)]>=ki) return que(ls(n1),cl,mid,ki,tp);
	else return (tp?sum[ls(n1)]:0)+que(rs(n1),mid+1,cr,ki-sz[ls(n1)],tp);

}
int n;ll k;
void solve()
{
	cin>>n>>k;
	rep(i,1,n) cin>>a[i],a[i]-=i,b[i]=a[i];
	sort(b+1,b+n+1,[&](ll x,ll y){return x<y;});
	int tot=unique(b+1,b+n+1)-b-1;
	rep(i,1,n) a[i]=lower_bound(b+1,b+tot+1,a[i])-b;
	rt=build(1,tot);
	int ans=1,p=1;
	rep(i,1,n)
	{
		while(p<=n)
		{
			
			modify(rt,1,tot,a[p],1);
			int ki=(p-i+1)>>1;
			ll v1=que(rt,1,tot,ki,1);
			ll v2=que(rt,1,tot,p-i+1,1)-v1;
			if((p-i+1)%2==0)
			{
				if(v2-v1<=k) 
					ans=max(ans,p-i+1),p++;
				else
				{
					modify(rt,1,tot,a[p],-1);
					break;
				}
			}
			else
			{
				ll v3=que(rt,1,tot,ki+1,0);
				if(v2-v1-v3<=k)
					ans=max(ans,p-i+1),p++;
				else
				{
					modify(rt,1,tot,a[p],-1);
					break;
				}
			}
		}
		modify(rt,1,tot,a[i],-1);
		if(p>n) {ans=max(ans,n-i+1); break;}
	}
	cout<<ans<<"\n";
}
int main()
{
	IOS
	int t=1;cin>>t;
	while(t--) solve();
	return 0;
}
/*
5
7 5
7 2 5 5 4 11 7
6 0
100 3 4 5 99 100
5 6
1 1 1 1 1
5 50
100 200 300 400 500
1 100
3
*/