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

using namespace std;

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

const int LIM = 1000005;

int N;
int Last, answer;
int Dist[LIM];
bool beenThere[LIM];

vector  < int > V[LIM];
queue   < int > qu;

void BFS(int n)
{
    int number;

    for(int i = 0; i < LIM; i++)
    {
        Dist[i] = 0;
        beenThere[i] = false;
    }

    qu.push(n);
    Dist[n] = 1;
    beenThere[n] = true;

    while(!qu.empty())
    {
        number = qu.front();
        for(int i = 0; i < V[number].size(); i++)
        {
            if(!beenThere[V[number][i]])
            {
                qu.push(V[number][i]);

                Dist[V[number][i]] = Dist[number] + 1;
                beenThere[V[number][i]] = true;
                answer = Dist[V[number][i]];

                Last = V[number][i];
            }
        }
        qu.pop();
    }
}

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

int main()
{
    Read();
    BFS(1);
    cout << Last;
    BFS(Last);
    fout << answer;
    return 0;
}