#include<bits/stdc++.h>
#define int long long
#define endl '\n';
using namespace std;
const int N=1e6+10;
int p[N];
set<int>xx[N];
int fa[N];
vector<int>ye;
void dfs(int mu){
	if(xx[mu].size()==1&&mu!=1){
		ye.push_back(mu);
	//cout<<mu<<" ";
		return;
	}
	for(auto it:xx[mu]){
		if(it==fa[mu])continue;
		fa[it]=mu;
		dfs(it);
	}
}
void solve(){
	int n;
	cin>>n;
	for(int i=1;i<=n;i++){
		xx[i].clear();
	}
	
	for(int i=2;i<=n;i++){
		int b;
		cin>>b;
		xx[i].insert(b);
		xx[b].insert(i);
	}
	xx[1].insert(-1);
	if(n==1){
		cout<<1<<endl;
		return;
	}
	ye.clear();
	fa[1]=-1;
	dfs(1);
	int minn=1e18;
	int bb=ye.size();
	minn=min(minn,bb);
	int now=0;
	
	while(ye.size()>1){
		now++;
		vector<int>yy;
		for(auto it:ye){
			xx[fa[it]].erase(it);
			if(xx[fa[it]].size()==1){
				
				yy.push_back(fa[it]);
			}
		}
		ye=yy;
		int mm=yy.size();
		minn=min(minn,now+mm);
	}
	minn=min(minn,now+1);
	cout<<minn<<endl;
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int T=1;
	cin>>T;
	while(T--){
		solve();
	}
}