#include <algorithm>
#include <bitset>
#include <cassert>
#include <cstdio>
using namespace std;
const int N = 2000001;
int read() {
    char c = getchar();
    int x = 0;
    while (c < 48 || c > 57)
        c = getchar();
    do
        x = (x * 10) + (c ^ 48), c = getchar();
    while (c >= 48 && c <= 57);
    return x;
}
bitset<1 << 22> w;
int c[1 << 21];
int res, lim, bt, cb, dlt, nd;
int *g[N], f[N], s[N], d[N], n;
inline void upd(int x, int v) {
    c[x] += v;
    if (c[x] and c[x] == v) {
        int t = x + lim;
        while (t > 1 and w[t ^ 1])
            w.set(t), t >>= 1;
        w.set(t);
        return;
    }
    if (!c[x] and c[x] != v) {
        int t = x + lim;
        while (w[t])
            w.reset(t), t >>= 1;
        return;
    }
}
int sx[N], sv[N], tp;
inline void inc(int p, int cur) {
    cur ^= f[p];
    upd(cur, 1);
    for (int i = 0; i < d[p]; ++i)
        sx[tp] = g[p][i], sv[tp++] = cur;
}
inline void dec(int p, int cur) {
    cur ^= f[p];
    upd(cur, -1);
    for (int i = 0; i < d[p]; ++i)
        sx[tp] = g[p][i], sv[tp++] = cur;
}
int tx[N], ps[N];
bitset<N> tt;
int rk;
inline void sol(int p, bool del) {
    f[p] = 0;
    for (int i = 0; i < d[p]; ++i)
        f[p] ^= s[g[p][i]];
    for (int i = 1; i < d[p]; ++i) {
        inc(g[p][i], dlt);
        while (tp)
            --tp, inc(sx[tp], sv[tp]);
    }
    upd(dlt, 1);
    dlt ^= f[p];
    nd = 1, cb = bt;
    while (nd < lim) {
        --cb;
        nd = nd << 1 | (dlt >> cb & 1);
        if (w[nd])
            nd ^= 1;
    }
    nd -= lim;
    nd ^= dlt;
    f[p] ^= nd;
    dlt ^= nd;
    s[p] = nd;
    if (p == 1)
        res ^= nd;
    if (del) {
        dec(p, dlt);
        while (tp)
            --tp, dec(sx[tp], sv[tp]);
    }
}
inline void ca(int p, bool del) {
    int &t = ps[rk - 1];
    if (t > d[p])
        sol(p, del), --rk;
    else if (t == d[p])
        tx[rk] = g[p][0], ps[rk] = 1, tt[rk++] = 0, ++t;
    else
        tx[rk] = g[p][t], ps[rk] = 1, tt[rk++] = 1, ++t;
}
inline void solve() {
    n = read();
    dlt = 0, lim = 1, bt = 0;
    while (lim <= n)
        lim <<= 1, ++bt;
    for (int i = 2; i <= n; ++i)
        ++d[s[i] = read()];
    for (int i = 1; i <= n; ++i)
        g[i] = new int[d[i]], d[i] = 0;
    for (int i = 2; i <= n; ++i)
        g[s[i]][d[s[i]]++] = i;
    for (int i = n; i; --i) {
        s[i] = 1;
        for (int j = 0; j < d[i]; ++j) {
            s[i] += s[g[i][j]];
            if (s[g[i][0]] < s[g[i][j]])
                swap(g[i][0], g[i][j]);
        }
    }
    ps[0] = 1, tx[0] = 1, tt[0] = 1, rk = 1;
    while (rk)
        ca(tx[rk - 1], tt[rk - 1]);
    for (int i = 1; i <= n; ++i) {
        f[i] = d[i] = 0;
        delete[] g[i];
    }
}
int main() {
    int tc = read();
    while (tc--)
        solve();
    printf("%d\n", res);
    return 0;
}