#include <bits/stdc++.h>
using namespace std;

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

const int N_MAX = 1e5;

int n;
vector<int> gr[N_MAX + 2];
int depth[N_MAX + 2];

int last, maxDepth;

void dfs(int node, int daddy)
{
    if(depth[node] > maxDepth)
    {
        maxDepth = depth[node];
        last = node;
    }

    for(auto it: gr[node])
        if(it != daddy)
        {
            depth[it] = depth[node] + 1;
            dfs(it, node);
        }
}

int main()
{
    in >> n;
    for(int i = 1; i < n; i++)
    {
        int x, y;
        in >> x >> y;
        gr[x].push_back(y);
        gr[y].push_back(x);
    }

    dfs(1, 0);

    depth[last] = 1;
    dfs(last, 0);

    out << maxDepth << '\n';

    return 0;
}