#include <fstream>
#include <iostream>
#include <vector>
#include <iterator>
#include <cstring>

#define MAXN 100002

using namespace std;

typedef vector<vector<int>> Graph;

Graph graph;

bool visited[MAXN];

int dfs(int node)
{
    int dist = 0;

    visited[node] = true;
    for (int neighbor : graph[node])
    {
        if (visited[neighbor] == false)
        {
            dist = max(dist, dfs(neighbor));
        }
    }
    
    return dist + 1;
}

void findFurthestNode(int node, int dist, int & furthest)
{
    static int furthestDist = 0;

    bool hasNeighbors = false;
    
    //cout << "At " << node + 1 << endl;

    visited[node] = true;
    for (int neighbor : graph[node])
    {
        if (visited[neighbor] == false)
        {
            hasNeighbors = true;
            findFurthestNode(neighbor, dist + 1, furthest);
        }
    }
    
    if (hasNeighbors == false && dist > furthestDist)
    {
        //cout << node + 1 << " " << dist << endl;

        furthestDist = dist;
        furthest = node;
    }
}

int main()
{
    int n;
    fstream fin("darb.in", fstream::in);
    fstream fout("darb.out", fstream::out);

    fin >> n;
    //cout << n << endl;
    
    graph.resize(MAXN);

    for (int i=0; i<n-1; ++i)
    {
        int x, y;
        fin >> x >> y;
        //cout << x << " " << y << endl;
        
        graph[x-1].push_back(y-1);
        graph[y-1].push_back(x-1);
    }
    
    /*for (int i=0; i<n; ++i)
    {
        cout << i+1 << " ---> ";
        for (int node : graph[i])
        {
            cout << node+1 << " ";
        }
        cout << endl;
    }*/
    
    int root = 0;
    int dist = 0;
    
    visited[0] = true;

    findFurthestNode(0, 0, root);
    
    //cout << root + 1 << endl;
    
    memset(visited, 0, sizeof(visited));

    dist = 0;

    visited[root] = true;
    for (int node : graph[root])
    {
        dist = max(dist, dfs(node));
    }

    fout << dist + 1 << endl;
    
    return 0;
}