#include<fstream>
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#define pb push_back
using namespace std;
const int MAX_N = 100005;

vector<int> G[MAX_N], sub;
int n;

inline int comp(int a, int b)
{
    return a>b;
}

int dnm(int k)
{
    if(G[k].size()==0)
        return 0;
    else
    {
        sub.clear();
        int q=0;
        for(int i=0; i<G[k].size(); i++)
            sub.pb(dnm(G[k][i]));
        sort(sub.begin(), sub.end() , comp);
        for(int i=0; i<sub.size(); i++)
            sub[i]+=(++q);
        return *max_element(sub.begin(), sub.end());
    }
}

int main()
{
    int T, i, a, b;
    ifstream fin("zvon.in");
    freopen("zvon.out", "w", stdout);
    fin>>T;
    while(T--)
    {
        for(i=1; i<=n; i++)
            G[i].clear();
        fin>>n;
        for(i=1; i<n; i++)
        {
            fin>>a>>b;
            G[a].pb(b);
        }
        printf("%d\n", dnm(1));
    }
    return 0;
}