#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <cstring>

using namespace std;

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

int t,n;

vector<int> L[100005];
int R[100005];

void read(){
    int x,y;
    in>>n;
    for(int i=1;i<n;i++){
        in>>x>>y;
        L[x].push_back(y);
    }
}
bool cmp(int a, int b){
    return R[a]>R[b];
}
int dfs(int st){
    int c=1;
    for(auto x : L[st]){
        dfs(x);
    }
    sort(L[st].begin(),L[st].end(),cmp);
    for(auto x : L[st]){
        R[st]=max(R[st],R[x]+c);
        c++;
    }
}
void solve_t(){
    dfs(1);
    out<<R[1]<<"\n";
    memset(R,0,sizeof(R));
    for(int i=1;i<=n;i++){
        L[i].clear();
    }
}
void solve(){
    in>>t;
    for(int o=1;o<=t;o++){
        read();
        solve_t();
    }
}
int main(){
    solve();
    return 0;
}