#include <iostream>
#include <fstream>
#include <vector>

#define Max 100001

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int N, M;
bool visited[Max];
int max_level, pos_level;

class Graph{
private:
    int NumberOfNodes, NumberOfEdges;
    vector<int> adjacencyList[Max];
    
public:
    Graph(int N, int M); // constructor
    void Read_UndirectedGraph();
    void DFS(int node, int level);
    void Darb();
};

// constructor
Graph :: Graph(int N, int M)
{
    NumberOfNodes = N;
    NumberOfEdges = M;
}

void Graph :: Read_UndirectedGraph()
{
    for ( int i = 1; i <= NumberOfEdges; i++ )
    {
        int x, y;
        fin >> x >> y;
        adjacencyList[x].push_back(y);
        adjacencyList[y].push_back(x);
    }
}

void Graph :: DFS(int node, int level)
{
    visited[node] = 1;
    if ( level > max_level )
    {
        max_level = level;
        pos_level = node;
    }
    for ( auto i : adjacencyList[node])
    {
        int next = adjacencyList[node][i];  // vecinul
        if ( !visited[next] )
            DFS(next, level+1);
    }
}

void Graph :: Darb()
{
    DFS(1,0);
s
    // resetare
    for ( int i = 1; i <= NumberOfNodes; i++ )
        visited[i] = 0;
    
    DFS(pos_level, 0);
    fout << max_level + 1;
}

int main()
{
    fin >> N;
    Graph G(N,N-1);
    G.Read_UndirectedGraph();
    G.Darb();

    return 0;
}