//#include <iostream>
#include <bits/stdc++.h>
using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");
const int Max=100005;
vector < int >v[Max];
int n,m,dist[Max],dmax,frmax; bool viz[Max];
queue < int >q;
void citire()
{
    in>>n; m=n-1;
    for(int i=1;i<=m;i++)
    {
       int x,y; in>>x>>y;
       v[x].push_back(y);
       v[y].push_back(x);
    }
}
void bfs(int nodd)
{
    for(int i=1;i<=n;i++)
        viz[i]=0;
    q.push(nodd);
    viz[nodd]=1;
    dist[nodd]=1;
    while(!q.empty())
    {
        int nod=q.front(); q.pop();
        for(int j=0;j<v[nod].size();j++)
        {
            int vecin=v[nod][j];
            if(!viz[vecin])
            {
                viz[vecin]=1;
               dist[vecin]=dist[nod]+1;
               dmax=dist[vecin];
               frmax=vecin;
               q.push(vecin);
            }
        }
    }
}
int main()
{
   citire();
   bfs(1);
   bfs(frmax);
   out<<dmax;
    return 0;
}