#include <bits/stdc++.h>
#define maxN 100005
using namespace std;
int T,n,i,j,x,y,dp[maxN];
vector<int>v[maxN];
bool cmp(const int &a,const int &b)
{
    return dp[a]>dp[b];
}
void dfs(int nod)
{
    for(auto it:v[nod])
        dfs(it);
    sort(v[nod].begin(),v[nod].end(),cmp);
    dp[nod]=0;
    for(int i=0;i<v[nod].size();i++)
        dp[nod]=max(dp[nod],dp[v[nod][i]]+i+1);
}
int main()
{
    freopen("zvon.in","r",stdin);
    freopen("zvon.out","w",stdout);
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n);
        for(i=1;i<=n;i++){
            v[i].clear();
            dp[i]=0;
        }
        for(i=1;i<n;i++)
        {
            scanf("%d %d",&x,&y);
            v[x].push_back(y);
        }
        dfs(1);
        printf("%d\n",dp[1]);
    }
    return 0;
}