#include <cstdio>
#include <vector>
#include <queue>
using namespace std;
const int Nmax = 100010;
vector <int> graf[Nmax];
queue<int> coada;
int viz[Nmax],contor[Nmax],elfinal,n;

void bfs(int start)
{
    int nod;
    coada.push(start);
    viz[start]= 1;
    contor[start] = 1;
    while(!coada.empty())
    {
        nod = coada.front();
        coada.pop();
        for(vector <int> :: iterator it = graf[nod].begin() ; it!= graf[nod].end() ; it++)
        {
            if(viz[*it] == 0)
            {
                viz[*it] = 1;
                coada.push(*it);
                contor[*it] = contor[nod] + 1;
                elfinal= *it;
            }
        }
    }

}

void reset()
{
    for(int i = 0 ; i < n ; i++)
        viz[i] = 0;
}

void read()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    int x,y;
    for(int i = 0 ; i < n-1; i ++)
    {
        scanf("%d %d",&x,&y);
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
}
int main()
{
    read();
    bfs(1);
    reset();
    bfs(elfinal);
    printf("%d",contor[elfinal]);
    return 0;
}