#include<vector>
#include<algorithm>
#include<stdio.h>
using namespace std;
int t,n,i,a[100000][2];
int df(int vf)
{vector <int> v;
 int i,min,j;
 min=0;
 for(i=1;i<=n;i++)
 {if(a[i][0]==vf)
   v.insert(v.end(),df(a[i][1])+1);}
 std::sort(v.begin(),v.end());
 for(i=v.size()-1,j=0;i>=0;i--,j++)
  if(v[i]+j>min) min=v[i]+j;
 return min;}

int main()
{freopen("zvon.in","r",stdin);
 freopen("zvon.out","w",stdout);
 scanf("%d",&t);
 for(;t;t--)
 {scanf("%d",&n);
  for(i=1;i<n;i++) scanf("%d %d",&a[i][0],&a[i][1]);
  if(n==1) printf("0\n");
  else printf("%d\n",df(1));}
 fclose(stdout);
 return 0;}