// http://infoarena.ro/problema/zvon
#include <fstream>
#include <algorithm>
#include <vector>
using namespace std;

#define maxSize 100001

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

vector<int> graph[maxSize];

void read();
int depthFirst(int node);

int main() {
    int tests;
    in >> tests;

    for(int i=1;i<=tests;i++) {
        read();
        out << depthFirst(1) << "\n";
    }

    in.close();
    out.close();

    return (0);
}

void read() {
    int nodes,father,son;
    in >> nodes;

    for(int i=1;i<nodes;i++)
        graph[i].clear();

    for(int i=1;i<nodes;i++) {
        in >> father >> son;
        graph[father].push_back(son);
    }
}

int depthFirst(int node) {
    vector<int> dist;

    vector<int>::iterator it,end;
    end = graph[node].end();
    for(it=graph[node].begin();it!=end;++it)
        dist.push_back(depthFirst(*it));

    sort(dist.begin(),dist.end());

    int stop = dist.size();
    int maxim = 0;
    for(int i=0;i<stop;i++)
        maxim = max(maxim,dist[i]+stop-i);

    return maxim;
}