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