#include <fstream>
#include <vector>
#include <cstring>
#include <queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");

vector<int>g[100001];
int d[100001], n, x, y, dmax, node;
queue<int>q;

void Bfs(int x)
{
    d[x]=1;
    q.push(x);
    while(!q.empty())
    {
        x=q.front();q.pop();
        node=x;
        for(vector<int>::iterator it=g[x].begin();it<g[x].end(); it++)
        {
            if(!d[*it])
            {
                q.push(*it);
                d[*it]=d[x]+1;
                dmax=max(dmax,d[*it]);
            }
        }
    }
}

int main()
{
    fin>>n;
    for(int i = 1; i< n; i++ )
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    Bfs(1);
    memset(d,0,sizeof(d));
    Bfs(node);
    fout<<dmax;
    fin.close();
    fout.close();
    return 0;
}