#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;

const int MAXN = 1e6 + 10;
const int INF = 1e9;

inline int read() {
	int x = 0, f = 1;
	char ch = getchar();
	while (!isdigit(ch)) {
		if (ch == '-') f = -1;
		ch = getchar();
	}
	while (isdigit(ch)) {
		x = x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}

vector<int> G[MAXN];
int n, sum[MAXN], dist[MAXN];

void dfs(int u, int fa) {
	if (G[u].size() == 1 && fa != -1) {
		dist[u] = 0;
		return;
	}
	for (auto x:G[u]) {
		if (x == fa) continue;
		dfs(x, u);
		dist[u] = max(dist[u], dist[x] + 1);
	}
}

int main() {
	int q = read();
	while (q--) {
		n = read();
		for (int i = 2; i <= n; i++) {
			int pa = read();
			G[pa].push_back(i);
			G[i].push_back(pa);
		}
		for (int i = 0; i <= n; i++) sum[i] = 0;
		dfs(1, -1);
		for (int i = 1; i <= n; i++) sum[dist[i]]++;
		int minn = INF;
		for (int i = 0; i <= n; i++) {
			minn = min(minn, i + sum[i]);
		}
		cout << minn << endl;
		for (int i = 1; i <= n; i++) G[i].clear();
		for (int i = 1; i <= n; i++) dist[i] = 0;
	}
	return 0;
}