#include <bits/stdc++.h>

using namespace std;

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

int n, m, viz[100005], d[100005];
vector < int > L[100005];

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

int main()
{
    int x, y, mx = 0, i, nod;
    fin >> n;
    for(i = 1; i < n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    DFS(1);
    for(i = 1; i <= n; i++)
    {
        viz[i] = 0;
        if(d[i] > mx)
        {
            mx = d[i];
            nod = i;
        }
        d[i] = 0;
    }
    mx = 0;
    DFS(nod);
    for(i = 1; i <= n; i++)
        mx = max(d[i], mx);
    fout << (mx + 1) << "\n";
    fin.close();
    fout.close();
    return 0;
}