#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 df(int x){
	int i,y;
	FOR(i,1,cati[x])
		df(cine[x][i]);
	if (cati[x]>0)
		cine[x][0]=0;
	qsort(cine[x]+1,cati[x],sizeof(int),cmp);
	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);
}