//horatiu11
# include <cstdio>
# include <vector>
# include <algorithm>
# define nmax 100001
using namespace std;
int t,n,x,y,T[nmax];
vector <int>G[nmax];
inline bool cmp(int a, int b)
{return (T[a]>T[b]);}
inline void dfs(int x)
{
    vector <int>::iterator it;int nr;
    for(it=G[x].begin();it!=G[x].end();++it)
        dfs(*it);
    sort(G[x].begin(),G[x].end(),cmp);
    for(it=G[x].begin(),nr=0;it!=G[x].end();++it,++nr)
        T[x]=max(T[x],T[*it]+nr+1);
}
int main()
{
    int i;
    freopen("zvon.in","r",stdin);
    freopen("zvon.out","w",stdout);
    scanf("%d",&t);
    while(t)
    {
        scanf("%d",&n);
        for(i=1;i<n;++i)
        {
            scanf("%d%d",&x,&y);
            G[x].push_back(y);
        }
        dfs(1);
        printf("%d\n",T[1]);
        for(i=1;i<=n;++i)
            G[i].clear(),T[i]=0;
        --t;
    }
    return 0;
}