#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin ("darb.in");
ofstream fout ("darb.out");
int n,i,j,cate[100005],best,maxi,viz[100005],x,y,nou,viz2[100005];
vector <int> liste[100005];
void dfs(int nod, int dist)
{
    viz[nod]=1;
    if(dist>maxi)
    {
        best=nod;
        maxi=dist;
    }
    for(int i=0;i<=cate[nod]-1;i++)
    {
        nou=liste[nod][i];
        if(viz[nou]==0)
        {
            dfs(nou,dist+1);
        }
    }
}
void dfs2(int nod, int dist)
{
    viz2[nod]=1;
    maxi=max(maxi,dist);
    for(int i=0;i<=cate[nod]-1;i++)
    {
        nou=liste[nod][i];
        if(viz2[nou]==0)
        {
            dfs2(nou,dist+1);
        }
    }
}
int main()
{
    fin>>n;
    while(fin>>x>>y)
    {
        liste[x].push_back(y);
        liste[y].push_back(x);
        cate[x]++;cate[y]++;
    }
    dfs(1,0);
    maxi=0;
    dfs2(best,0);
    fout<<maxi+1;
    return 0;
}