#include <cstdio>
#define MAX1 100000
using namespace std;
struct vecini{
   int nod;
   vecini *next;
};
vecini *v[MAX1+1];
int fii[MAX1+1];
int max(int a, int b)
{
    if(a>b)
        return a;
    return b;
}
void adauga(int nod, int vecin)
{
    vecini *aux;
    aux=new vecini;
    aux->nod=vecin;
    aux->next=v[nod];
    v[nod]=aux;
    fii[nod]++;
}
int dfs(int nod)
{
    int maxim=0;
    vecini *aux;
    if(v[nod]==NULL)
        return 0;
    aux=v[nod];
    while(aux!=NULL)
    {
        maxim=max(maxim, dfs(aux->nod));
        aux=aux->next;
    }
    return max(fii[nod], maxim+1);
}
int main()
{
    freopen("zvon.in", "r", stdin);
    freopen("zvon.out", "w", stdout);
    int i, t, n, a, x, y;
    scanf("%d", &t);
    for(a=1;a<=t;a++)
    {
        scanf("%d", &n);
        for(i=1;i<n;i++)
        {
            scanf("%d%d", &x, &y);
            adauga(x, y);
        }
        printf("%d\n", dfs(1));
        for(i=1;i<=n;i++){
            v[i]=0;
            fii[i]=0;
        }
    }
    return 0;
}