#include<stdio.h>
#include<vector>
#include<algorithm>
using namespace std;
FILE *f=fopen("zvon.in","r"),*g=fopen("zvon.out","w");
vector <int> v[100001];
int n,i,t[100001],x,y,j;
void dfs(int k){
    int OK=0;
    for(int i=0;i<v[k].size();i++){
        OK=1;
        dfs(v[k][i]);
  if(OK==1)
    if(t[v[k][i]]==0)
        t[k]++;
    else
        t[k]=max(t[k],t[v[k][i]]+1);
    }
}
int main(){
    int T;
    fscanf(f,"%d",&T);
    for(i=1;i<=T;i++)
    {
        fscanf(f,"%d",&n);
        for(j=1;j<=n-1;j++){
            fscanf(f,"%d %d",&x,&y);
            v[x].push_back(y);
        }
        dfs(1);
        fprintf(g,"%d\n",t[1]);
        for(j=1;j<=n;j++){
            v[j].clear();
            t[j]=0;}
    }
    return 0;
}