#include <cstdio>
#include <algorithm>
#include <queue>
#define N 100010

using namespace std;

typedef struct noduri
{
    int val;
    noduri *urm;
} adr;

adr *L[N],*p;
int rez[N],V[N],fii[N],t,n,i,x,y,maxim;
queue<int> C;

bool cmp(int i, int j)
{
    return (fii[i]>fii[j]);
}

void dfs(int nod)
{
    adr *p;
    for (p=L[nod]; p; p=p->urm)
    {
        dfs(p->val);
        fii[nod]+=fii[p->val];
    }
}

void zvon() //care e fapt un bfs
{
    adr *p;
    int i,kont;
    for (C.push(1); !C.empty(); C.pop())
    {
        kont=0;
        for (p=L[C.front()]; p; p=p->urm)
        {
            V[++kont]=p->val;
            C.push(p->val);
        }
        sort(V+1,V+kont+1,cmp);
        for (i=1; i<=kont; i++)
        {
            rez[V[i]]=rez[C.front()]+i;
            if (rez[V[i]]>maxim) maxim=rez[V[i]];
        }
    }
}

int main()
{
    freopen("zvon.in","r",stdin);
    freopen("zvon.out","w",stdout);
    scanf("%d\n",&t);
    while (t--)
    {
        maxim=0;
        scanf("%d\n",&n);
        for (i=1; i<n; i++)
        {
            scanf("%d %d\n",&x,&y);
            p=new adr;
            p->val=y; p->urm=L[x];
            L[x]=p;
            fii[x]++;
        }
        dfs(1);
        zvon();
        //for (i=1; i<=n; i++) printf("%d ",rez[i]); printf("\n\n");
        printf("%d\n",maxim);
        for (; !C.empty(); C.pop());
        for (i=1; i<=n; i++)
        {
            L[i]=NULL;
            rez[i]=0;
            fii[i]=0;
        }
    }

    return 0;
}