#include <fstream>
using namespace std;
ifstream cin("stroll.in");
ofstream cout("stroll.out");
int a[1001],l1[1001],l2[1001],p,ans=0;
void dfs(int step,int x,int y)
{
	int r;
	if (x==0)
	{
		if (step>ans) ans=step;
	}else
	{
		for (r=1;r<=p;r++) if (a[r]==x) {dfs(step+1,l1[r],l2[r]);break;}
	}
	if (y==0)
	{
		if (step>ans) ans=step;
	}else
	{
		for (r=1;r<=p;r++) if (a[r]==y) {dfs(step+1,l1[r],l2[r]);break;}
	}
}
int main()
{
	int i,k;
	cin>>p;
	for (i=1;i<=p;i++)
	{
		cin>>a[i]>>l1[i]>>l2[i];
		if (a[i]==1) k=i;
	}
	dfs(1,l1[k],l2[k]);
	cout<<ans<<endl;
	return 0;
}