#include <bits/stdc++.h>
using namespace std;

#define ll long long 
#define lll __int128
#define INF 0x3f3f3f3f
#define LNF 0x3f3f3f3f3f3f3f3fll
#define MOD 998244353
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ld long double
#define fi first
#define se second
#define all(a) a.begin(), a.end()

#define N 1000010

vector<int> G[N];
int dep[N], mxd[N], lc[N];

void dfs(int u, int fa, int d) {
    dep[u] = d;
    mxd[u] = d;
    lc[u] = 0;
    for (auto& v : G[u]) {
        if (v == fa) continue;
        dfs(v, u, d+1);
        if (!lc[u] || mxd[lc[u]] < mxd[v]) lc[u] = v;
        mxd[u] = max(mxd[u], mxd[v] + 1);
    }
}

void dfs1(int u, int fa, int l, vector<int>& s) {
    int ct = 0;
    for (auto& v : G[u]) {
        if (v == fa) continue;
        ++ ct;
        if (v == lc[u]) dfs1(v, u, l+1, s);
        else dfs1(v, u, 1, s);
    }
    if (!ct) s.emplace_back(l);
}

int main() {
#ifdef TEST
    freopen("zz.in", "r+", stdin);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int q; cin >> q;
    while (q --) {
        int n; cin >> n;
        for (int i = 0; i <= n; ++ i) G[i].clear();
        for (int i = 2; i <= n; ++ i) {
            int p; cin >> p;
            G[i].emplace_back(p);
            G[p].emplace_back(i);
        }
        dfs(1, 1, 1);
        vector<int> lnk;
        dfs1(1, 1, 1, lnk);

        sort(all(lnk));
        int res = lnk.size();
        for (int i = 0; i < lnk.size(); ++ i) res = min(res, lnk[i] + (int) lnk.size() - (i+1));
        cout << res << '\n';
    }
}