#include <bits/stdc++.h>

using namespace std;

bool v[100005];

vector<int> graf[100005];
int startNode;

ifstream f("darb.in");
ofstream g("darb.out");

int maxDiam = -1;

int DFS(int nod, int diam)
{
    v[nod] = true;
    if(diam > maxDiam)
    {
        maxDiam = diam;
        startNode = nod;
    }
    for (int i = 0; i < graf[nod].size(); i++)
    {
        if (!v[graf[nod][i]])
        {
            DFS(graf[nod][i], diam + 1);
        }
    }
}

int main()
{
    int N;
    f >> N;
    for (int i = 0, a, b; i < N - 1; i++)
    {
        f >> a >> b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }
    DFS(1, 1);
    int copieStart = startNode;
    for(int i = 0; i < N; i++)
    {
        v[i] = false;
    }
    DFS(copieStart, 1);
    g << maxDiam;
}