#include<stdio.h>
#include<algorithm>
#include<vector>
using namespace std;
#define nmax 100005
long a, b, n, i, ii, t, tmin[nmax], poz;
vector <long> ma[nmax], v[nmax];

void citire()
{
    scanf("%ld",&n);
    for (i=1;i<=n;i++)
        ma[i].clear();
    for (i=1;i<=n-1;i++)
    {
        scanf("%ld %ld",&a,&b);
        ma[a].push_back(b);
    }
}

bool cmp(long a, long b)
{   return a>b; }

void dfs(long nod)
{
    vector <long> ::iterator it;
    v[nod].clear();
    for (it=ma[nod].begin();it!=ma[nod].end();it++)
    {
        dfs(*it);
        v[nod].push_back(tmin[*it]);
    }
    sort(v[nod].begin(),v[nod].end(),cmp);
    tmin[nod]=0;    poz=0;
    for (it=v[nod].begin();it!=v[nod].end();it++)
    {
        poz++;
        if (tmin[nod]<*it+poz)
            tmin[nod]=*it+poz;
    }
}

int main()
{
    freopen("zvon.in","r",stdin);
    freopen("zvon.out","w",stdout);
    scanf("%ld",&t);
    for (ii=1;ii<=t;ii++)
    {
        citire();
        dfs(1);
        printf("%ld\n",tmin[1]);
    }
    return 0;
}