#include<fstream>
#include<queue>
#include<vector>
std::ifstream fin("darb.in");
std::ofstream fout("darb.out");
const int NMAX=100005;
int n;
std::vector<int>G[NMAX];
void read()
{
    fin>>n;
    for(int i=0; i<n-1; ++i)
    {
        int from, to;
        fin>>from>>to;
        G[from].push_back(to);
        G[to].push_back(from);
    }
}
inline int bfs(int start, int &cost)
{
    int final;
    cost=-1;
    std::vector<int>dist(n+1, -1);
    std::queue<int>q;
    q.push(start);
    dist[start]=1;
    while(!q.empty())
    {
        int node=q.front();
        if(cost<dist[node])
        {
            final=node;
            cost=dist[node];
        }
        q.pop();
        for(auto it:G[node])
            if(dist[it]==-1)
            {
                dist[it]=dist[node]+1;
                q.push(it);
            }
    }
    return final;
}
int main()
{
    int d=0;
    read();
    int aux=bfs(1, d);
    bfs(aux, d);
    fout<<d;
    return 0;
}