#include <bits/stdc++.h>
#define NMAX 100010
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
deque <pair <int,int> > coada;
vector <int> l_a[NMAX];
int viz[NMAX];
int nod_f, dist, x, y, i, nod, pasi, n;
void dfs(int &nod_f,int ok, int &dist)
{
    coada.push_back({nod_f,1});
    viz[nod_f]=ok+1;
    while(coada.size()!=0)
    {
        nod=coada.front().first;
        pasi=coada.front().second;
        coada.pop_front();
        for(i=0; i<l_a[nod].size(); i++)
        {
            if(viz[l_a[nod][i]]==ok)
            {
                viz[l_a[nod][i]]=ok+1;
                coada.push_back({l_a[nod][i],pasi+1});
            }
        }
    }
    nod_f=nod;
    dist=pasi;
}
int main()
{
    f>>n;
    for(i=1; i<n; i++)
    {
        f>>x>>y;
        l_a[x].push_back(y);
        l_a[y].push_back(x);
    }
    nod_f=1;
    dfs(nod_f,0,dist);
    dist=0;
    dfs(nod_f,1,dist);
    g<<dist;
    return 0;
}