#include <bits/stdc++.h>
using namespace std;
const int N = 2e5+10;
int fa[N];
vector<int>e[N];
int dep[N];
void dfs(int r,int f){
    dep[r] = dep[f] + 1;
    if(e[r].size() == 1 && r != 1){
        return;
    }
    for(int i = 0;i<e[r].size();i++){
        if(e[r][i] == f) continue;
        dfs(e[r][i],r);
    }
}
void solve(){
    int n;
    cin >> n;
    for(int i = 1;i<n;i++){
        cin >> fa[i];
        e[i + 1].push_back(fa[i]);
        e[fa[i]].push_back(i + 1);
    }
    dfs(1,0);
    int ans = 0;
    for(int i = 1;i<=n;i++){
        ans = max(ans,dep[i] - 1);
    }
    cout << ans << endl;
    for(int i = 1;i<=n;i++){
        e[i].clear();
        dep[i] = 0;
    }
}
int main(){
    int t;
    cin >> t;
    while(t--){
        solve();
    }
    return 0;
}