#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstring>
#include <stack>
#define NMAX 100001

using namespace std;

int cost[NMAX], viz[NMAX];
int N, T;

bool cmp(int a, int b)
{
    if(cost[a] > cost[b])
    {
        return 1;
    }
    return 0;
}

void mark(vector< vector<int> > &v, int nod)
{
    int max, c, curent;
    vector<int>::iterator it;
    stack<int> S;
    int vec[NMAX];

    memset(vec, 0, sizeof(vec));

    S.push(nod);
    viz[nod] = 1;

    while(!S.empty())
    {
        curent = S.top();

        if(vec[curent])
        {
            S.pop();
            sort(v[curent].begin(), v[curent].end(), cmp);
            max = 0;
            c = 1;

            for(it=v[curent].begin();it!=v[curent].end();it++)
            {
                if(max < c + cost[*it])
                {
                    max = c + cost[*it];
                }
                c++;
            }
            cost[curent] = max;
        }

        for(it=v[curent].begin();it!=v[curent].end();it++)
        {
            if(!viz[*it])
            {
                viz[*it] = 1;
                S.push(*it);
            }
        }
        vec[curent] = 1;
    }
}

void solve()
{
    vector< vector<int> > v(NMAX);
    int i, x, y;

    scanf("%d", &N);
    for(i=0;i<N-1;++i)
    {
        scanf("%d %d", &x, &y);
        v[x].push_back(y);
    }

    memset(cost, 0, sizeof(cost));
    memset(viz, 0, sizeof(viz));

    mark(v, 1);
}


int main()
{
    freopen("zvon.in", "r", stdin);
    freopen("zvon.out", "w", stdout);

    scanf("%d", &T);

    while(T--)
    {
        solve();
        printf("%d\n", cost[1]);
    }

    return 0;
}