#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define inf 0x3f3f3f3f
#define db double
#define il inline
#define x first
#define y second
#define endl '\n'
const int N = 2e6 + 5;
const int mod = 998244353;

vector<int> g[N];
// 深度，   部分链长，父节点，重儿子， 链头，  dfs序，  子树最大dfs序，dfs序对应节点
int dep[N], len[N], fa[N], hson[N], top[N], dfsn[N], mdfsn[N], node[N], cnt;
void dfs1(int u, int d = 1)
{
    len[u] = 1, dep[u] = d;
    for (auto v: g[u])
    {
        if (!dep[v])
        {
            dfs1(v, d + 1);
            fa[v] = u;
            if (len[v] + 1 > len[u])
                hson[u] = v, len[u] = len[v] + 1;
        }
    }
}
void dfs2(int u, int tp)
{
    dfsn[u] = ++cnt;
    top[u] = tp;
    node[cnt] = u;
    if (hson[u]) dfs2(hson[u], tp);
    for (auto v: g[u])
        if (!top[v]) dfs2(v, v);
    mdfsn[u] = cnt;
}
void cut(int r = 1)
{
    dfs1(r);
    dfs2(r, r);
}
int a[N];
void solve()
{
    int n;
    cin >> n;
    cnt = 0;
    
    for (int i = 2; i <= n; i++) 
    {
        int f; cin >> f;
        g[f].push_back(i), g[i].push_back(f);
    }
    cut();
    int cnt = 0;
    for (int i = 1; i <= n; i++) 
    {
        if (top[i] == i) 
        {
            a[++cnt] = len[i];
        }
    }
    sort(a + 1, a + cnt + 1);
    int ans = inf;
    for (int i = cnt; i >= 0; i--)
    {
        ans = min(ans, cnt - i + a[i]);
    }
    cout << ans << '\n';

    for (int i = 0; i <= n; i++)
    {
        dep[i] = len[i] = fa[i] = hson[i] = top[i] = dfsn[i] = mdfsn[i] = node[i] = 0;
        g[i].clear();
    }
}
signed main()
{
    // freopen("D:\\3022244240\\vscode\\txt\\in.txt", "r", stdin);
    // freopen("D:\\3022244240\\vscode\\txt\\out.txt", "w", stdout);
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int T = 1; cin >> T;
    while (T--) solve();
    return 0;
}

/*
3
8
1 2 3 4 1 5 6
1
5
1 2 2 2
*/