#include <fstream>
#include <stdlib.h>
#include <stdio.h>
using namespace std;

int tree[200001][3];
int hgt = -1;

void height(int curr, int h){
    hgt = (h > hgt) ? h : hgt;
    if (tree[curr][1] != 0){
        height(tree[curr][1], h+1);
    }
    if (tree[curr][2] != 0){
        height(tree[curr][2], h+1);
    }

}
int main() {
    ifstream fin("height.in");
    ofstream fout("height.out");

    int n, i, temp;
    fin >> n;
    if (n == 0){
        fout << 0;
        return 0;
    }

    for (i = 1; i <= n; i++) {
        fin >> tree[i][0];
        fin >> tree[i][1];
        fin >> tree[i][2];
    }

    height(1, 1);

    fout << hgt;
    return 0;
}