#include <cstdio>
#include <cstdlib>
#include <vector>
#include <algorithm>
using namespace std;
const int MAXN=1011;
vector<int> map[MAXN];
int P,C,x,y,Ans,deep=1;
bool flag[MAXN]={0};
inline int Max(int a,int b) {return a>b?a:b;}

void dfs(int now)
{
	for(unsigned int i=0;i<map[now].size();i++)
	{
		x=map[now][i];
		if(x==0) {Ans=Max(Ans,deep);continue;}
		deep++; dfs(x); deep--;
	}
}

int main()
{
	freopen("stroll.in","r",stdin);
	freopen("stroll.out","w",stdout);
	scanf("%d\n",&P);
	for(int i=1;i<=P;i++)
	{
		scanf("%d %d %d\n",&C,&x,&y);
		map[C].push_back(x);
		map[C].push_back(y);
	}
	dfs(1);
	printf("%d\n",Ans);
	return 0;
}