#include<bits/stdc++.h>
#define ll long long

using namespace std;

const int N = 1e6 + 10;
int n, cnt[N], f[N];
vector<int>e[N];

void dfs(int u)
{
    for (auto v : e[u])
    {
        dfs(v);
        f[u] = max(f[v] + 1, f[u]);
    }
    cnt[f[u]]++;
}

void solve()
{
    cin >> n;
    for (int i = 0; i <= n; i++)e[i].clear(), f[i] = 0, cnt[i] = 0;
    for (int i = 2; i <= n; i++)
    {
        int p; cin >> p;
        e[p].push_back(i);
    }
    dfs(1);
    int res = f[1] + 1;
    for (int i = 0; i <= f[1]; i++)
    {
        res = min(res, i + cnt[i]);
    }
    cout << res << '\n';
}

int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t; cin >> t;
    while (t--)solve();
    return 0;
}