# include <bits/stdc++.h>

using namespace std;

const int Nmax = 1e5 + 5;

vector <int> G[Nmax];
int n, distM, nodeM;

void read()
{
    for (int i = 1; i <= n; ++i)
    {
        int x, y;
        scanf("%d %d\n", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

int dfs(int node, int dad, int dist)
{
    for (auto &it: G[node])
    {
        if (it == dad) continue;
        dfs(it, node, dist + 1);
    }

    if (dist > distM) distM = dist, nodeM = node;
}

int compute()
{
    distM = 0;
    dfs(1, 0, 0);
    dfs(nodeM, 0, 0);
    return distM + 1;
}

int main ()
{
    freopen("darb.in", "r", stdin);
    freopen("darb.out", "w", stdout);

    scanf("%d\n", &n);

    read();
    printf("%d\n", compute());

    return 0;

}