#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");

const int Nmax = 100005;
int n, Level[Nmax], Use[Nmax], ultim, cost[Nmax], sol, Lmax;
vector <int> G[Nmax];
queue <int> Q;

void DFS(int nod, int tata)
{
    for(int i = 0; i < (int)G[nod].size(); i++)
    {
        int vecin = G[nod][i];
        if(vecin == tata) continue;
        Level[vecin] = Level[nod]+1;
        if(Lmax < Level[vecin])
        {
            Lmax = Level[vecin];
            ultim = vecin;
        }
        DFS(vecin, nod);
    }
}

void BFS(int prim)
{
    Q.push(prim);
    Use[prim] = 1;
    while(!Q.empty())
    {
        int nod = Q.front();
        Q.pop();
        for(int i = 0; i < (int)G[nod].size(); i++)
        {
            int vecin = G[nod][i];
            if(!Use[vecin])
            {
                Use[vecin] = 1;
                cost[vecin] = cost[nod]+1;
                Q.push(vecin);
                //cout<<cost[vecin]<<' ';
                if(sol < cost[vecin]) sol = cost[vecin];
            }
        }
    }
}

int main()
{
    f>>n;
    for(int i = 1; i <= n; i++)
    {
        int x, y;
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    Level[1] = 1;
    DFS(1,0);
    BFS(ultim);
    g<<sol+1<<'\n';
    return 0;
}