#include <bits/stdc++.h>

using namespace std;

int n,T,sol;
vector<int> L[100003];

ifstream fin("zvon.in");
ofstream fout("zvon.out");

inline void Citire()
{
    int i,x,y;
    fin>>n;
    for(i=1;i<n;++i)
    {
        fin>>x>>y;
        L[min(x,y)].push_back(max(x,y));///minim???
    }
}

inline void DFS(int x,int c)
{
    int w;
    unsigned int k;
    sol=max(sol,c);
    for(k=0;k<L[x].size();++k)
    {
        w=L[x][k];
        DFS(w,c+1);
    }
}

inline void Solutie()
{
    int i;
    for(i=1;i<=n;++i)
        sort(L[i].begin(),L[i].end());
    DFS(1,1);
    fout<<sol<<"\n";
}

inline void Reinit()
{
    int i;
    for(i=1;i<=n;++i)
        L[i].clear();
    sol=0;
}

int main()
{
    int i,j;
    fin>>T;
    for(i=1;i<=T;++i)
    {
        Citire();
        if(n==1)    fout<<"0\n";
        else    Solutie();
        Reinit();
    }
    return 0;
}