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

using namespace std;

vector <int> v[100001];
queue <int> q;
int n, a, b, vd[100001];
ifstream fin("darb.in");
ofstream fout("darb.out");

int bfs()
{
    int p;
    while(!q.empty())
    {
        p = q.front();
        q.pop();
        for(auto x : v[p])
        {
            if(vd[x] == 0)
            {
                q.push(x);
                vd[x] = vd[p] + 1;
            }
        }
        if(q.empty())
            return p;
    }
}

void rst()
{
    for(int i = 1; i<=100000; i++)
        vd[i] = 0;
}

int main()
{
    fin>>n;
    for(int i = 1; i<=n-1; i++)
    {
        fin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    q.push(1);
    vd[1] = 1;
    q.push(bfs());
    rst();
    vd[q.front()] = 1;
    int z = bfs();
    fout<<vd[z];
}