#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 1e5;
vector<int>g[NMAX + 5];

int lst;
int ans;

void dfs (int u, int p = -1, int d = 1)
{
    if (d > ans)
        ans = d, lst = u;
    for (const auto &v : g[u])
    {
        if (p != v)
            dfs(v, u, d+1);
    }
}

int main()
{
    int n;
    in >> n;
    for (int i=1; i<n; i++)
    {
        int u, v;
        in >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }

    dfs(1);
    ans = 0;
    dfs(lst);
    out << ans;

    return 0;
}