#include <bits/stdc++.h>

using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int n,d[100003];
vector<int>h[100003];
bitset<100003>viz;

void Citire()
{
    int i,x,y;
    fin>>n;
    for(i=1;i<n;i++)
    {
        fin>>x>>y;
        h[x].push_back(y);
        h[y].push_back(x);
    }
}

void DFS(int nod, int dist)
{
    viz[nod] = true;
    d[nod] = dist;
    for(auto i : h[nod])
        if(viz[i] == false)
            DFS(i,dist+1);
}

void Rezolvare()
{
    int i,nod,mx;
    mx = 0;
    DFS(1,1);
    for(i=1;i<=n;i++)
        if(viz[i] == true && d[i] > mx)
        {
            nod = i;
            mx = d[i];
        }
    viz.reset();
    DFS(nod,1);
    mx = 0;
    for(i=1;i<=n;i++)
        mx = max(mx,d[i]);
    fout<<mx<<"\n";
}

int main()
{
    Citire();
    Rezolvare();

    fin.close();
    fout.close();
    return 0;
}