/*[[
 ⣇⣿⠘⣿⣿⣿⡿⡿⣟⣟⢟⢟⢝⠵⡝⣿⡿⢂⣼⣿⣷⣌⠩⡫⡻⣝⠹⢿⣿⣷ ]],[[
 ⡆⣿⣆⠱⣝⡵⣝⢅⠙⣿⢕⢕⢕⢕⢝⣥⢒⠅⣿⣿⣿⡿⣳⣌⠪⡪⣡⢑⢝⣇ ]],[[
 ⡆⣿⣿⣦⠹⣳⣳⣕⢅⠈⢗⢕⢕⢕⢕⢕⢈⢆⠟⠋⠉⠁⠉⠉⠁⠈⠼⢐⢕⢽ ]],[[
 ⡗⢰⣶⣶⣦⣝⢝⢕⢕⠅⡆⢕⢕⢕⢕⢕⣴⠏⣠⡶⠛⡉⡉⡛⢶⣦⡀⠐⣕⢕ ]],[[
 ⡝⡄⢻⢟⣿⣿⣷⣕⣕⣅⣿⣔⣕⣵⣵⣿⣿⢠⣿⢠⣮⡈⣌⠨⠅⠹⣷⡀⢱⢕ ]],[[
 ⡝⡵⠟⠈⢀⣀⣀⡀⠉⢿⣿⣿⣿⣿⣿⣿⣿⣼⣿⢈⡋⠴⢿⡟⣡⡇⣿⡇⡀⢕ ]],[[
 ⡝⠁⣠⣾⠟⡉⡉⡉⠻⣦⣻⣿⣿⣿⣿⣿⣿⣿⣿⣧⠸⣿⣦⣥⣿⡇⡿⣰⢗⢄ ]],[[
 ⠁⢰⣿⡏⣴⣌⠈⣌⠡⠈⢻⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣬⣉⣉⣁⣄⢖⢕⢕⢕ ]],[[
 ⡀⢻⣿⡇⢙⠁⠴⢿⡟⣡⡆⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣵⣵⣿ ]],[[
 ⡻⣄⣻⣿⣌⠘⢿⣷⣥⣿⠇⣿⣿⣿⣿⣿⣿⠛⠻⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿ ]],[[
 ⣷⢄⠻⣿⣟⠿⠦⠍⠉⣡⣾⣿⣿⣿⣿⣿⣿⢸⣿⣦⠙⣿⣿⣿⣿⣿⣿⣿⣿⠟ ]],[[
 ⡕⡑⣑⣈⣻⢗⢟⢞⢝⣻⣿⣿⣿⣿⣿⣿⣿⠸⣿⠿⠃⣿⣿⣿⣿⣿⣿⡿⠁⣠ ]],[[
 ⡝⡵⡈⢟⢕⢕⢕⢕⣵⣿⣿⣿⣿⣿⣿⣿⣿⣿⣶⣶⣿⣿⣿⣿⣿⠿⠋⣀⣈⠙ ]],[[
 ⡝⡵⡕⡀⠑⠳⠿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠿⠛⢉⡠⡲⡫⡪⡪⡣ ]],*/
#include<bits/stdc++.h>
#define pb push_back
#define x first
#define y second
using namespace std;
using ll =long long ;
using pii =pair<int,int>;
using pll=pair<ll,ll>;
using pcc=pair<char,char>;
bool cmp(pll a,pll b){
	return a.y<b.y;
}
struct cmp1{
    bool operator()(pair<ll,ll>a,pair<ll,ll>b){
	if(a.x==b.x)return a.y>b.y;
	return a.x>b.x; 
}
};
const int mod=998244353;
ll ksm(ll a,ll b){
	ll ans=1;
	while(b){
		if(b&1){
			ans*=a;
		ans=ans%mod;
		}
		a=a*a;a%=mod;
		b>>=1;
	}
	return ans;
}
ll gcd(ll a,ll b){
	ll t=a%b;
	while(t){
		a=b;
		b=t;
		t=a%b;
	}
	return b;
}
ll lcm(ll a,ll b){
	return a/gcd(a,b)*b;
}
ll get_inv(ll x){
	return ksm(x,mod-2);
}
const int N=1e6+10;
ll a[N];
void solve(){
	int n;ll k;
	cin>>n>>k;
	ll base=0,basex=0;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		a[i]-=i;
	}
	ll mx=0;
	ll res=0;
	set<ll>zh,fu;
	//priority_queue<ll,vector<ll>,greater<>>zh;
	//priority_queue<ll,vector<ll>,>fu;
	int lenzh=0,lenfu=0;
	unordered_map<ll,int>mp;
	int l=1;
	for(int i=1;i<=n;i++){
		mp[a[i]]++;
		res+=abs(a[i]-base);
		if(a[i]==base)basex++;
		if(a[i]<base){
			if(mp[a[i]]==1)fu.insert(a[i]);
			lenfu++;
		}
		if(a[i]>base){
			if(mp[a[i]]==1)zh.insert(a[i]);
			lenzh++;
		}
		while(res>k){
			while(lenfu>basex+lenzh){
				auto t=--fu.end();
				int w=*t;
				res-=abs(w-base)*(lenfu-basex-lenzh);
				lenfu-=mp[w];
				zh.insert(base);
				lenzh+=basex;
				base=w;
				fu.erase(t);
				basex=mp[w];
			}
			while(lenzh>basex+lenfu){
				auto t=zh.begin();
				int w=*t;
				res-=abs(w-base)*(lenzh-lenfu-basex);
				lenzh-=mp[w];
				fu.insert(base);
				lenfu+=basex;
				base=w;
				basex=mp[w];zh.erase(t);
			}
			if(res>k){
				mp[a[l]]--;
				res-=abs(a[l]-base);
				if(mp[a[l]]==0){
					if(base<a[l])zh.erase(zh.find(a[l]));
					if(base>a[l])fu.erase(fu.find(a[l]));
				}
				if(base==a[l])basex--;
				if(base<a[l])lenzh--;
				if(base>a[l])lenfu--;
				l++;
			}
		}
		mx=max(mx,(ll)i-l+1);
	}
	cout<<mx<<endl;
}
int main(){
	ios::sync_with_stdio(false);cin.tie(0);
	int _=1;
	cin>>_;
	while(_--)solve();
	return 0;
}