#include <fstream>
#include <vector>
#include <queue>
#define NMAX 100005
#define inf 2000000000

using namespace std;

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

int i, n, x, y, d[NMAX], start, maxim = -1, ans = -1;
vector < int > v[NMAX];
queue < int > q;

void BFS(int node)
{
    q.push(node);

    while (!q.empty())
    {
        int curr = q.front();
        q.pop();

        for (auto & it : v[curr])
            if (d[it] > d[curr] + 1)
        {
            d[it] = d[curr] + 1;
            q.push(it);
        }
    }
}

int main()
{
    f >> n;

    for (i = 1; i <= n - 1; ++ i)
    {
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    for (i = 2; i <= n; ++ i)
        d[i] = inf;

    BFS(1);

    for (i = 1; i <= n; ++ i)
        if (d[i] > maxim)
    {
        maxim = d[i];
        start = i;
    }

    for (i = 1; i <= n; ++ i)
        d[i] = inf;
    d[start] = 0;

    BFS(start);

    for (i = 1; i <= n; ++ i)
        ans = max(ans, d[i]);

    g << ans + 1 << '\n';
    return 0;
}