#include <fstream>
#include <vector>
using namespace std;

ifstream cin("darb.in");
ofstream cout("darb.out");

#define MAX 100005

int n, a, b, maxim, nmax;
vector<int> g[MAX];

void dfs(int nod, int tata, int h)
{
    if(h > maxim)
    {
        nmax = nod;
        maxim = h;
    }
    for(int i = 0; i < g[nod].size(); ++i)
    {
        if(g[nod][i] != tata)
        {
            dfs(g[nod][i], nod, h + 1);
        }
    }
}

int main()
{
    cin >> n;
    for(int i = 1; i <= n - 1; ++i)
    {
        cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    maxim = 0;
    dfs(1, -1, 1);
    int nodmax = nmax;
    maxim = 0;
    dfs(nodmax, -1, 1);
    cout << maxim << '\n';
    return 0;
}