#include <bits/stdc++.h>

using namespace std;

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

vector <int> Muchii[100001];
queue <int> q;

int n, d[100001], p, maxim;
int main()
{
    fin >> n;
    for(int i = 1; i < n; i++)
    {
        int x, y;
        fin >> x >> y;
        Muchii[x].push_back(y);
        Muchii[y].push_back(x);
    }

    for(int i = 2; i <= n; i++)
        d[i] = -1;

    q.push(1);

    while(!q.empty())
    {
        int k;
        k = q.front();
        maxim = k;
        q.pop();

        for(int i = 0; i < Muchii[k].size(); i++)
        {
            int Vecin = Muchii[k][i];
            if(d[Vecin] == -1)
            {
                q.push(Vecin);
                d[Vecin] = d[k] + 1;

            }
        }

    }
    for(int i = 1; i <= n; i++)
        d[i] = -1;
    d[maxim] = 0;
    q.push(maxim);

    while(!q.empty())
    {
        int k;
        k = q.front();
        maxim = d[k];
        q.pop();

        for(int i = 0; i < Muchii[k].size(); i++)
        {
            int Vecin = Muchii[k][i];
            if(d[Vecin] == -1)
            {
                q.push(Vecin);
                d[Vecin] = d[k] + 1;
            }
        }
    }

    fout << maxim+1;
    return 0;
}