#include <cstdio>  
#include <algorithm>  
#include <vector>  
using namespace std;  
  
const int N = 60000;
  
int n;  
int d[N];  
vector<int> v[N];  
  
inline int max ( int a, int b ) { return (a > b) ? a : b; }  
  
void df ( int x ) {  
    vector<int> t;  
    for (int i = 0; i < v[x].size(); ++i) {  
        df(v[x][i]);  
        t.push_back(d[v[x][i]]);  
    }  
    sort(t.begin(),t.end());  
    if (t.size()>0) {  
        d[x] = t[t.size()-1]+1;  
        for (int i = 0; i < t.size(); ++i) {  
            d[x] = max(d[x],t[i]+t.size()-i);  
        }  
    }
}

/*while (scanf(" %s", ss2)==1)
	{
		l = strlen(ss2);
		val = 0;
		pp = 1;
		for (i = 0; i < l; i++) val = val+(ss2[i]-cst)*pp, pp *= 3;
		hash = val&S;
		t = 0;
		while ((V[hash]>0)&&(Val[hash]!=val)) hash = (hash+(++t))&S;
		V[hash] = 1; Val[hash] = val;
	}

	cst = 'a';
	val = 0; pp = 1;
	for (i = 0; i < l; i++) val = val+(ss[i]-cst)*pp, pp *= 3;
	p = pp/3;
	hash = val&S; Nr+=V[hash];
*/
int main()
{
    freopen("zvon.in","rt",stdin);  
    freopen("zvon.out","wt",stdout);  
    int t;  
    for (scanf("%d",&t); t > 0; --t) {  
        scanf("%d",&n);  
        for (int i = 0; i<N; ++i) {  
            v[i].clear();  
            d[i] = 0;  
        }  
        for (int i = 0; i < n-1; ++i) {  
            int a,b;  
            scanf("%d %d",&a,&b);  
            --a; --b;  
            v[a].push_back(b);  
        }  
        df(0);  
        printf("%d\n",d[0]);  
    }  
    return 0;  
}