#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");

const int MAX=1e5;
vector <int> muchii[MAX+5];
int q,nod1,nod2,sol,n,i;
bool viz[MAX+5];

void dfs(int nod,int adancime)
{
    viz[nod]=1;

    if (adancime>sol)
    {
        nod2=nod;
        sol=adancime;
    }

    for (auto x: muchii[nod])
        if (viz[x]==0)
            dfs(x,adancime+1);
}

int main()
{
    fin>>n;

    for (i=1; i<n; i++)
    {
        fin>>nod1>>nod2;

        muchii[nod1].push_back(nod2);
        muchii[nod2].push_back(nod1);
    }

    dfs(1,1);

    for (i=1; i<=n; i++)
        viz[i]=0;

    sol=0;
    dfs(nod2,1);

    fout<<sol;




    return 0;
}