#include<fstream>
#include<vector>
#include<algorithm>
using namespace std;
ifstream fin("zvon.in");
ofstream fout("zvon.out");
vector <int> v[100001];
int t,n,x,y,D[100001];

bool help(int A, int B)
{
    return D[A]>D[B];
}

void dfs(int nod)
{
    int i;
    for(i=0;i<v[nod].size();++i)
        dfs(v[nod][i]);

    sort(v[nod].begin(),v[nod].end(),help);

    if (v[nod].size()==0)
    {
        D[nod]=0;
        return ;
    }

    D[nod]=D[v[nod][0]]+1;

    for(i=1;i<v[nod].size();++i)
        D[nod]=max(D[nod],D[v[nod][i]]+i+1);
}

int main()
{
    int i,j;

    fin>>t;

    for (j=0;j<t;++j)
    {
        fin>>n;
        for (i=1;i<=n;++i)
            v[i].clear();

        for (i=1;i<n;++i)
        {
            fin>>x>>y;
            v[x].push_back(y);
        }

        dfs(1);

        fout<<D[1]<<"\n";
    }

  return 0;
}