#include <bits/stdc++.h>
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
vector <int> v[100009];
int n;
int ans[100009];
void bfs (int nod)
{
    for (int i=1; i<=n; i++)
        ans[i]=1e9;
    ans[nod]=0;
    queue <int> q;
    q.push(nod);
    while (!q.empty())
    {
        int x=q.front();
        q.pop();
        for (auto y:v[x])
        {
            if (ans[x]+1<ans[y])
            {
                ans[y]=ans[x]+1;
                q.push(y);
            }
        }
    }
}
signed main ()
{
    f >> n;
    for (int i=1; i<n; i++)
    {
        int x, y;
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    bfs (1);
    int nod=0;
    int maxim=0;
    for (int i=1; i<=n; i++)
    {
        if (ans[i]>maxim)
        {
            maxim=ans[i];
            nod=i;
        }
    }
    bfs (nod);
    maxim=0;
    for (int i=1; i<=n; i++)
    {
        if (ans[i]>maxim)
        {
            maxim=ans[i];
            nod=i;
        }
    }
    g << ++maxim;
}