#include <iostream>

struct Node {
    int parent;
    Node() : parent(-1) {}
};

int dfs(int node, int depth, Node* nodes) {
    if (nodes[node].parent == -1) return depth;
    int total_depth = 0;
    int parent = nodes[node].parent;
    total_depth += dfs(parent, depth + 1, nodes);
    return total_depth;
}

int main() {
    int n;
    std::cin >> n;
    Node* nodes = new Node[n + 1];
    for (int i = 0; i < n - 1; ++i) {
        int x, y;
        std::cin >> x >> y;
        nodes[y].parent = x;
    }
    int result = dfs(1, 0, nodes);
    std::cout << result << std::endl;
    delete[] nodes;
    return 0;
}