#include <bits/stdc++.h>

using namespace std;
ifstream fin ("darb.in");
ofstream fout ("darb.out");
const int NMAX=1e5+5;
int n,viz[NMAX],x,y,maxim,indice;
queue <int> q;
vector <int> G[NMAX];
int main()
{
    fin>>n;
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    q.push(1);
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(int i=0;i<G[nod].size();i++)
        {
            if(!viz[G[nod][i]] && G[nod][i]!=1)
            {
                viz[G[nod][i]]=viz[nod]+1;
                q.push(G[nod][i]);
                if(maxim<viz[G[nod][i]])
                {
                    indice=G[nod][i];
                    maxim=viz[G[nod][i]];
                }
            }
        }
    }


    maxim=0;
    q.push(indice);
    for(int i=1;i<=n;i++) viz[i]=0;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(int i=0;i<G[nod].size();i++)
        {
            if(!viz[G[nod][i]] && G[nod][i]!=indice)
            {
                viz[G[nod][i]]=viz[nod]+1;
                q.push(G[nod][i]);
                if(maxim<viz[G[nod][i]])
                {
                    maxim=viz[G[nod][i]];
                }
            }
        }
    }

    fout<<maxim+1;
    return 0;
}