#include <bits/stdc++.h>

using namespace std;

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

const int NMax = 1e5 + 5;

bool Used[NMax];

vector < int > G[NMax];

int Solve(const int &node){
    vector < int > A;
    Used[node] = 1;
    for(auto it: G[node]){
        if(!Used[it]){
            A.push_back(Solve(it));
        }
    }
    sort(A.begin(), A.end());
    int M = 0, k = A.size();
    for(auto it: A){
        M = max(M, it + k);
        k--;
    }
    return M;
}

int main(){
    int t, n, a, b;
    fin >> t;
    while(t--){
        fin >> n;
        for(int i = 1; i < n; i++){
            fin >> a >> b;
            G[a].push_back(b);
            G[b].push_back(a);
        }
        fout << Solve(1) << "\n";
        for(int i = 1; i <= n; i++) G[i].clear();
        memset(Used, 0, sizeof(Used));
    }
    return 0;
}