#include <bits/stdc++.h>
#define in "darb.in"
#define out "darb.out"
#define Nmax 100003
using namespace std;
ifstream fin(in);
ofstream fout(out);

int n;
int d[Nmax];
bitset <Nmax> viz;
vector <int> L[Nmax];

void Read()
{
    int i,x,y;

    fin >> n;
    for (i = 1; i < n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS(int k)
{
    viz[k] = 1;
    for (auto i : L[k])
        if (viz[i] == 0)
        {
            d[i] = d[k] + 1;
            DFS(i);
        }
}

void Solve()
{
    int p,maxi = -(1 << 30),i;

    d[1] = 1;
    DFS(1);

    /// aflu nodul cu dist maxima
    for (i = 1; i <= n; i++)
        if (d[i] > maxi)
        {
            maxi = d[i];
            p = i;
        }
    viz.reset();
    fill(d+1,d+n+1,0);

    d[p] = 1;
    DFS(p); maxi = -(1 << 30);
    for (i = 1; i <= n; i++)
        maxi = max(maxi,d[i]);
    fout << maxi << "\n";
}

int main()
{
    Read();
    Solve();

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