#include <fstream>
#include <vector>
#include <cstring>
const int NMAX = 100003;
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");

int n,i,sol,start,x,y;
bool used[NMAX];
vector <int> G[NMAX];

void DFS(int nod, int nivel)
{
    int i;
    used[nod]=1;
    if (nivel>sol)
    {
        sol=nivel;
        start=nod;
    }
    for (i=0;i<G[nod].size();i++)
    {
        if (!used[G[nod][i]])
        {
            DFS(G[nod][i],nivel+1);
        }
    }
}

int main()
{
    f>>n;
    for (i=1;i<=n-1;i++)
    {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1,1);
    memset(used,0,sizeof used);
    DFS(start,1);
    g<<sol;
    f.close();
    g.close();
    return 0;
}