#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
queue < pair <int, int > > q;
vector <int > graph[100005];
int lg[100005] ,n;
void init()
{
    for(int i = 1; i <= n; i++)
        lg[i] = -1;
}
void citire()
{
    fin >> n;
    init();
    for(int i = 0; i < n - 1; i++)
    {
        int x,y;
        fin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
}
void bfs(int st){
    lg[st] = 0;
    q.push({st, 0});
    while(!q.empty()){
        int vf = q.front().first;
        int lc = q.front().second + 1;
        for(auto &v : graph[vf])
            if(lg[v] == -1){
                q.push({v, lc});
                lg[v] = lc;
            }
        q.pop();
    }
}
int cautmax()
{
    int maxx = 0,nod;
    for(int i = 1; i <= n; i++)
        if(lg[i] > maxx)
        maxx = lg[i],nod = i;
    return nod;
}
int main()
{
    citire();
    bfs(1);
   int maxi = cautmax();
   init();
   bfs(maxi);
   fout <<lg[cautmax()] + 1;

    return 0;
}