#include <fstream>
#include <vector>

using namespace std;

const int N = 1e5;

vector <int> a[N+1];
int d1[N+1], dp[N+1];

void dfs(int x, int t, int d[])
{
    d[x] = 1 + d[t];
    for (auto y: a[x])
    {
        if (d[y] == 0)
        {
            dfs(y, x, d);
        }
    }
}

int maxim(int v[], int n)
{
    int pmax = 1;
    for (int i = 2; i <= n; i++)
    {
        if (v[i] > v[pmax])
        {
            pmax = i;
        }
    }
    return pmax;
}

int main()
{
    ifstream in("darb.in");
    ofstream out("darb.out");
    int n;
    in >> n;
    for (int i = 1; i < n; i++)
    {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1, 0, d1);
    int p = maxim(d1, n);
    dfs(p, 0, dp);
    out << dp[maxim(dp, n)];
    in.close();
    out.close();
    return 0;
}