/*
    Rescriere OLI 2015
    Start: 10:45
*/

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

using namespace std;

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

const int NLIM = 100005;

int N;
int maxLevel, posLevel;
vector  < int > V[NLIM];

bool beenThere[NLIM];

void DFS(int Node, int level)
{
    beenThere[Node] = true;
    if(level > maxLevel)
    {
        maxLevel = level;
        posLevel = Node;
    }
    for(unsigned int i = 0; i < V[Node].size(); i++)
    {
        int Next = V[Node][i];
        if(!beenThere[Next])
            DFS(Next, level + 1);
    }
}

void Reset()
{
    for(int i = 1; i <= N; i++)
        beenThere[i] = false;
}

void Read()
{
    int x, y;
    fin >> N;
    for(int i = 1; i < N; i++)
    {
        fin >> x >> y;
        V[x].push_back(y);
        V[y].push_back(x);
    }
    DFS(1,0);

    Reset();

    DFS(posLevel,0);
    fout << maxLevel + 1;
}

int main()
{
    Read();
    return 0;
}