#include <bits/stdc++.h>

using namespace std;

struct sp
{
    int k;
    int l;
    int r;
};

int n, k = 0, i, m;
sp a[200010];

void dfs(int ind)
{
    k++;
    if(k > m)
        m = k;

    if (a[ind].l != 0)
        dfs(a[ind].l - 1);

    if (a[ind].r != 0)
        dfs(a[ind].r - 1);

    k--;
}

int main()
{
    //ifstream in("height.in");ofstream out("height.out");

    cin >> n;
    if (!n)
    {
        cout << 0;
        return 0;
    }
    for(i = 0; i < n; i++)
        cin >> a[i].k >> a[i].l >> a[i].r;

    dfs(0);

    cout << m;
    return 0;
}