#include <bits/stdc++.h>

using namespace std;

using vi = vector<int>;


void solve() {
    int n;
    cin >> n;
    vector<vi> e(n + 1);
    vi dis(n + 1, 0);
    for (int i = 2, x; i <= n; i++)
        cin >> x, e[x].push_back(i);

    auto dfs = [e, &dis](auto &&self, int x) -> void {
        for (auto y: e[x])
            self(self, y), dis[x] = max(dis[x], dis[y] + 1);
        return;
    };
    dfs(dfs, 1);

    vi cnt(dis[1] + 1);
    for (int i = 1; i <= n; i++)
        cnt[dis[i]]++;
    int res = INT_MAX;
    for (int i = 0; i <= dis[1]; i++)
        res = min(res, i + cnt[i]);
    cout << res << "\n";
}

int32_t main() {
    ios::sync_with_stdio(false), cin.tie(nullptr);
    int TC;
    for (cin >> TC; TC; TC--)
        solve();
    return 0;
}