#include <fstream>
using namespace std;

struct node
{
    int value;
    int left;
    int right;
};

int high(node* arr, int root)
{
    if (root<=-1) return 0;

    int left_branch = high(arr, arr[root].right);
    int right_branch = high(arr, arr[root].left);

    if (left_branch > right_branch) return (left_branch + 1);
    else return (right_branch + 1);

}


int main()
{
    fs_base::sync_with_stdio(false);
    Fin.tie(NULL);
    ifstream fin("height.in");
    ofstream fout("height.out");
    int i;
    fin >> i;
    node* binTree = new node[i];
    for (int j = 0; j < i; j++)
    {
        fin >> binTtree[j].value >> binTree[j].left >> binTree[j].right;
        binTree[j].right--;
        binTree[j].left--;
    }

    if (i !=0 ) fout << hight(binTree, 0);

    else fout << 0;

    return 0;
}