#include <cstdio>
#include <vector>
#define N 100001
#include<algorithm>
std::vector <int> v[N];
int val[N];
bool cmp(int a,int b){
    return val[a]>val[b];
}
void dfs(int nod){
    int i;
    for(i=0;i<v[nod].size();i++)
        dfs(v[nod][i]);
    std::sort(v[nod].begin(),v[nod].end(),cmp);
    for(i=0;i<v[nod].size();i++)
        if(val[v[nod][i]]+i+1>val[nod])
            val[nod]=val[v[nod][i]]+i+1;
}
int main()
{
    freopen("zvon.in","r",stdin);
    freopen("zvon.out","w",stdout);
    int t;
    scanf("%d",&t);
    while(t){
        int n,i;
        scanf("%d",&n);
        for(i=1;i<=n;i++){
            val[i]=0;
            v[i].clear();
        }
        for(i=0;i<n-1;i++){
            int x,y;
            scanf("%d%d",&x,&y);
            v[x].push_back(y);
        }
        dfs(1);
        printf("%d\n",val[1]);
        t--;
    }
    return 0;
}