#include<fstream>
#include<cstring>
#include<vector>
using namespace std;
ifstream f("zvon.in");
ofstream g("zvon.out");
bool viz[100001];
long long i,x,y,n,nr[100001],c[100001],t;
vector <int> a[100001];
void bfs(int k)
{
    int i,p,u;
    viz[k]=1;
    c[1]=k;
    nr[k]=1;
    p=u=1;
    while(p<=u)
    {
        y=c[p];
        for(i=0;i<a[y].size();i++)
        {
            if(viz[a[y][i]]==0)
            {
                u++;
                c[u]=a[y][i];
                nr[a[y][i]]=nr[y]+1;
                viz[a[k][i]]=1;
            }
        }
        p++;
    }
}
int main()
{
    f>>t;
    for(i=1;i<=t;i++)
    {
        f>>n;
        if(n==1) g<<"0"<<"\n";
        for(i=1;i<=n-1;i++)
        {
            f>>x>>y;
            a[x].push_back(y);
        }
        bfs(1);
        g<<nr[n]+1<<"\n";
        memset(viz, 0,sizeof(viz));
    }
    return 0;
}