#include <iostream>
#include <vector>
#include <fstream>
#include <cstring>
#define Nmax 100000
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int n,m,x,y,vx,lmax;
vector<int> g[Nmax + 5];
int viz[Nmax + 5];
void dfs(int nod)
{
    for(auto i : g[nod])
    {
        if(viz[i]==0)
        {
            viz[i]=viz[nod]+1;
            if(viz[i]>lmax)
            {
                lmax=viz[i];
                vx=i;
            }
            dfs(i);
        }
    }
}
int main()
{
    fin>>n;
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    viz[1]=1;
    dfs(1);
    //cout<<"nigga";
    for(int i=1;i<=n;i++)
        viz[i]=0;
    viz[vx]=1;
    dfs(vx);
    fout<<lmax;
    return 0;
}