#include <bits/stdc++.h>

using namespace std;

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

const int nmax=1e5+5;

vector <int> g[nmax];
int n, d[nmax];

void dfs (int node, int dist)
{
    d[node]=dist;
    for (auto i:g[node])
    {
        if (!d[i])
            dfs(i,dist+1);
    }
}


signed main()
{
    fin >> n;
    for (int i=1; i<n; i++)
    {
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,1);
    int dist=0, nod;
    for (int i=1; i<=n; i++)
    {
        if (d[i]>dist)
        {
            dist=d[i];
            nod=i;
        }
        d[i]=0;
    }
    dfs(nod,1);
    dist=0;
    for (int i=1; i<=n; i++)
        dist=max(dist,d[i]);
    fout << dist;
    return 0;
}