#include <iostream>
#include <fstream>
#include <vector>
using namespace std;


ifstream fin("darb.in");
ofstream fout("darb.out");


int n;
int maxim,nodi;
vector <int> g[100005];


void dfs(int nod,int tata,int dist)
{
    int s=g[nod].size();
    for(int i=0;i<s;i++)
    {
        int nnod=g[nod][i];
        if(nnod!=tata)dfs(nnod,nod,dist+1);
    }
    if(dist>maxim)
    {
        maxim=dist;
        nodi=nod;
    }
}


void solve()
{
    fin>>n;
    int x,y;
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,1,1);
    maxim=0;
    dfs(nodi,nodi,1);
    fout<<maxim;
}


int main()
{
    solve();
    return 0;
}