#include<cstdio>
#include<cstring>
using namespace std;
int n,i;
int d1[2000];
int d2[2000];
int dfs(int i){
	int x;
	int y;
	if (i==0) return 0;
	x=dfs(d1[i]);
	y=dfs(d2[i]);
	return x>y?x+1:y+1;
}
int main()
{
	freopen("stroll.in","r",stdin);
	freopen("stroll.out","w",stdout);
	scanf("%d",&n);
	for (i=1;i<=n;i++){
		scanf("%d",&i);
		scanf("%d%d",&d1[i],&d2[i]);
	}
	printf("%d",dfs(1));
	return 0;
}