#include <bits/stdc++.h>
#define int long long
#define x first
#define y second
using namespace std;
using LL = long long;
typedef pair<int, int> PII;
const int N = 1e5 + 10, M = 5010, mod = 1e9 + 7;
const int inf = 1e18;
void solve(){
	int n;
	cin >> n;
	vector <int> deg(n + 1), fa(n + 1);
	for(int i = 2; i <= n; i++){
		int x; cin >> x;
		fa[i] = x;
		deg[x]++;
	}
	queue <int> q;
	for(int i = 1; i <= n; i++){
		if(!deg[i]){
			q.push(i);		
		}
	}
	int ans = inf;
	int cnt = 0;//op2/删层的次数 
	while(q.size()){
		int tot = q.size();
		ans = min(ans, tot + cnt);
		cnt++;
		while(tot--){
			int t = q.front();
			q.pop();
			deg[fa[t]]--;
			if(deg[fa[t]] == 0) q.push(fa[t]);
		}
	}
	cout << ans << "\n";
}
signed main() {
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int T = 1;
	cin >> T;
	while(T--) {
		solve();
	}
}
/*
6
1 1 3 1 5
*/