#include <fstream>
#include <vector>
#include <cstring>
using namespace std ;
const int Nmax = 100002;
vector < int > Tree[Nmax];
int Dist[Nmax],start;
inline void Read(){
    int x, y ,i  ,N;
    ifstream f("darb.in");
    f >> N;
    for(i = 1;i < N; ++i){
        f >> x >> y;
        Tree[x].push_back(y);
        Tree[y].push_back(x);
    }
    f.close();
}

inline void DFS(const int node){
    if(Dist[node] > Dist[start])
        start = node;
    for(vector < int > :: iterator it = Tree[node].begin(); it != Tree[node].end(); ++it)
        if(Dist[*it]==0){
            Dist[*it] = Dist[node]+1;
            DFS(*it);
        }
}

inline void Solve(){
    Dist[1] = 1;
    DFS(1);
    memset(Dist,0,sizeof(Dist));
    Dist[start] = 1;
    DFS(start);
}

inline void Write(){
    ofstream g("darb.out");
    g<<Dist[start]<<"\n";
    g.close();
}

int main(){
    Read();
    Solve();
    Write();
    return 0;
}