#include <stdio.h>
#include <stdlib.h>
#define FOR(i,a,b) for(i=a;i<=b;++i)
#define N 100010
int t;
void start(void){
	freopen("zvon.in","r",stdin);
	freopen("zvon.out","w",stdout);
	scanf("%d",&t);
}
int n;
int *cine[N];
int timp[N],cati[N];
void scan(void){
	int i,x,y;
	scanf("%d",&n);
	FOR(i,1,n-1){
		scanf("%d%d",&x,&y);
		++cati[x];
		cine[x]=(int*)realloc(cine[x],cati[x]*sizeof(int)+4);
		cine[x][cati[x]]=y;
	}
}
int max(int a,int b){
	if (a>b)
		return a;
	return b;
}
int cmp(const void *a,const void *b){
	return timp[*(int*)b]-timp[*(int*)a];
}
void swap(int a,int b,int h[]){
	int aux;
	aux=h[a];
	h[a]=h[b];
	h[b]=aux;
}
void down_heap(int i,int nr,int h[]){
	int max=i;
	if (2*i<=nr && timp[h[max]] > timp[h[2*i]])
		max=2*i;
	if (2*i+1<=nr && timp[h[max]] > timp[h[2*i+1]])
		max=2*i+1;
	if (max!=i){
		swap(max,i,h);
		down_heap(max,n,h);
	}
}
void sort(int x){
	//qsort(cine[x]+1,cati[x],sizeof(int),cmp);
	int i,nr=cati[x];
	for (i=nr/2;i;--i)
		down_heap(i,nr,cine[x]);
	for (i=nr;i>1;--i){
		swap(1,i,cine[x]);
		down_heap(1,i-1,cine[x]);
	}
}
void df(int x){
	int i,y;
	FOR(i,1,cati[x])
		df(cine[x][i]);
	if (cati[x]>0)
		cine[x][0]=0;
	sort(x);
	FOR(i,1,cati[x]){
		y=cine[x][i];  
		timp[x]=max(timp[x],i+timp[y]);  
	}  
}
void solve(void){
	int i;
	FOR(i,1,n)timp[i]=0;
	df(1);
	FOR(i,1,n){
		cine[i]=(int*)realloc(cine[i],0);
		//free(cine[i]);
		cati[i]=0;
	}
	printf("%d\n",timp[1]);
}
int main(void){
	start();
	while(t--){
		scan();
		solve();
	}
	exit(0);
}