#include <cstdio>
#include <vector>
#include <queue>

#define maxN 100001

using namespace std;

vector <int> V[maxN];

class Comp
{
    public:
        bool operator()(int i, int j)
        {
            return
                V[i].size() < V[j].size();
        };
};

priority_queue <int, vector <int>, Comp> pq;

int T;
int N;
int Sol;

int Ti[maxN];
int Co[maxN];

void bf()
{
    int p, u, n, i, j, k, nod;

    p = 1;
    u = 1;
    
    Co[1] = 1;
    Ti[1] = 0;

    while(p <= u)
    {
        nod = Co[p];
        ++ p;

        n = V[nod].size();

        for(i=0; i<n; ++i)
        {
            pq.push(V[nod][i]);
            Co[++u] = V[nod][i];
        }

        V[nod].clear();

        j = 1;

        while(pq.empty() == false)
        {
            k = pq.top();
            pq.pop();

            Ti[k] = Ti[nod] + j;
            ++ j;

            Sol = Ti[k] > Sol ? Ti[k] : Sol;
        }
    }
}

int main()
{
    freopen("zvon.in", "rt", stdin);
    freopen("zvon.out", "wt", stdout);

    int i, a, b;

    for(scanf("%d", &T); T; --T)
    {
        for(scanf("%d", &N), i=1; i<N; ++i)
        {
            scanf("%d %d", &a, &b);
            V[a].push_back(b);
        }

        Sol = 0;
        bf();

        printf("%d\n", Sol);
    }

    return 0;
}