#include <fstream>
#include <vector>

using namespace std;

const char InFile[]="darb.in";
const char OutFile[]="darb.out";
const int MaxN=100111;

ifstream fin(InFile);
ofstream fout(OutFile);

int N,x,y,sol,viz[MaxN],solnod,phase;
vector<int> G[MaxN];

void DFS(int nod, int d=1)
{
    viz[nod]=phase;
    for(vector<int>::iterator it=G[nod].begin();it!=G[nod].end();++it)
    {
        if(viz[*it]!=phase)
        {
            DFS(*it,d+1);
        }
    }
    if(d>sol)
    {
        sol=d;
        solnod=nod;
    }
}

int main()
{
    fin>>N;
    for(register int i=1;i<N;++i)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    fin.close();

    ++phase;
    DFS(1);
    ++phase;
    DFS(solnod);

    fout<<sol;
    fout.close();
    return 0;
}