#include <stdio.h>

#define maxm 100001

int n,m,i,t,min;
int x[maxm],y[maxm],v[maxm],aa[maxm],fol[maxm];
int a[maxm];
int g[2*maxm];

void inter(int p, int q)
{
	int r=(p+q)/2,x,y,k=0;
	x=p;
	y=r+1;
	while (x<=r && y<=q)
	{
		k++;
		if (a[x]<a[y])
		{
			aa[k]=a[x];
			x++;
		}
		else
		{
			aa[k]=a[y];
			y++;
		}
	}
	while (x<=r)
	{
		k++;
		aa[k]=a[x];
		x++;
	}
	while (y<=r)
	{
		k++;
		aa[k]=a[y];
		y++;
	}
	int i;k=0;
	for (i=p; i<=q; i++)
	{
		k++;
		a[i]=aa[k];
	}
}
void merge(int p, int q)
{
	int r=(p+q)/2;
	if (p==q) return;
	merge(p,r);
	merge(r+1,q);
	inter(p,q);
	if (q<=p+1) return;
}

int df(int k)
{
	int i,p,q;
	for (i=g[k]; i<=g[k+1]-1; i++)
		if (fol[a[i]]==0)
		{
			fol[a[i]]=1;
			v[i]=df(a[i]);
			fol[a[i]]=0;
		}
	p=0;q=0;
	for (i=g[k+1]-1; i>=g[k]; i--)
	if (fol[a[i]]==0)
	{
		p++;
		if (v[i]+p>q) q=v[i]+p;
	}
	return q;
}
int main()
{
	freopen("zvon.in","r",stdin);
	freopen("zvon.out","w",stdout);

	scanf("%d",&n);
	for (t=1; t<=n; t++)
	{
		scanf("%d",&m);
		for (i=1; i<=m+1; i++)
		{
			g[i]=0;
			a[i]=0;
		}
		for (i=1;i<=m-1;i++)
		{
			scanf("%d %d ",&x[i],&y[i]);
			g[x[i]]++;
			g[y[i]]++;
		}

		for (i=2;i<=m+1;i++) g[i] += g[i-1];

		for (i=1;i<=m-1;i++)
		{
			a[g[x[i]]]= y[i];
			g[x[i]]--;
			a[g[y[i]]] = x[i];
			g[y[i]]--;
		}

		for (i=1;i<=m+1;i++) g[i]++;

		if (m!=1)
		for (i=1; i<=m; i++)
		{
			merge(g[i],g[i+1]-1);
			fol[i]=0;
		}
		fol[1]=1;
		printf("%d\n",df(1));
	}


	return 0;
}