#include <bits/stdc++.h>

using namespace std;

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

const int DIM = 1e5 + 7;

vector <int> v[DIM];

int d[DIM];

bitset <DIM> vis;

queue <int> q;

main()
{
    int n;
    in >> n;

    for(int i = 1; i < n; i++)
    {
        int x, y;
        in >> x >> y;

        v[x].push_back(y);
        v[y].push_back(x);
    }

    int last = 1;
    q.push(1);

    vis[1] = true;

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

        last = nod;

        for(auto i : v[nod])
            if(vis[i] == false)
            {
                vis[i] = true;
                q.push(i);
            }
    }

    int mx = 0;

    vis[last] = false;

    q.push(last);

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

        mx = max(mx, d[nod]);

        for(auto i : v[nod])
            if(vis[i] == true)
            {
                vis[i] = false;
                q.push(i);
                d[i] = d[nod] + 1;
            }
    }

    out << mx + 1;
}