#include<fstream>
#include<vector>
#include<bitset>
#include<queue>
#define Nmax 100099
using namespace std;
ifstream f("darb.in");
ofstream g("darb.out");
int n,x,y,d[Nmax],S,mare,sare;
vector <int> G[Nmax];
bitset <Nmax> viz;
queue <int> Q;
void BFS(int S){
    for(int i=1;i<=n;++i){
        d[i]=0;
        viz[i]=0;
    }
    sare=0;
    d[S]=0;
    viz[S]=1;
    Q.push(S);
    while(!Q.empty()){
        int node=Q.front();
        Q.pop();
        vector <int> :: iterator it;
        for(it=G[node].begin();it!=G[node].end();++it){
            if(viz[*it]==0){
                viz[*it]=1;
                d[*it]=d[node]+1;
                if(d[*it]>sare)
                {
                    mare=*it;
                    sare=d[*it];
                }
                Q.push(*it);
            }
        }
    }


}
int main()
{
    f>>n;
    for(int i=1;i<n;i++){
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    BFS(1);
    BFS(mare);
    g<<sare+1<<'\n';
    f.close();g.close();
    return 0;
}