#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
const int Nmax=100000+5;
int maxim=0,nodm,maximm=0;
vector <int >v[Nmax];
short viz[Nmax];
int n;
int DP[Nmax];
void DFS(int nod)
{
    viz[nod]=1;
    for(int i=0;i<v[nod].size();++i)
        if(viz[v[nod][i]]==0)
        {
            if(DP[v[nod][i]]>DP[nod]+1 or DP[v[nod][i]]==0)
                DP[v[nod][i]]=DP[nod]+1;
            viz[v[nod][i]]=1;
            if(DP[v[nod][i]]>maxim)
            {
                maxim=DP[v[nod][i]];
                nodm=v[nod][i];
            }
            DFS(v[nod][i]);
        }
}
void DFS2(int nod)
{
    viz[nod]=2;
    for(int i=0;i<v[nod].size();++i)
        if(viz[v[nod][i]]==1)
        {
            viz[v[nod][i]]=2;
            if(DP[v[nod][i]]>DP[nod]+1 or DP[v[nod][i]]==0)
                DP[v[nod][i]]=DP[nod]+1;
            if(DP[v[nod][i]]>maximm)
                maximm=DP[v[nod][i]];
            DFS2(v[nod][i]);
        }
}
int main()
{
    fin>>n;
    for(int i=1,x,y;i<n;++i)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    //for(int i=1;i<=n;++i,cout<<'\n')
        //for(int j=0;j<v[i].size();++j)
            //cout<<v[i][j]<<" ";
    for(int i=0;i<n;++i)
        if(v[i].size()>0)
        {
            viz[i]=1;
            DP[i]=0;
            DFS(i);
            break;
        }
    //for(int i=0;i<=n;++i)
        //cout<<DP[i]<<" ";
    for(int i=0;i<=n;++i)
        DP[i]=0;
    DP[maxim]=0;
    viz[nodm]=2;
    DFS2(nodm);
    maximm++;
    fout<<maximm;
    return 0;
}