#include <bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");

int N, nod1, nod2, m1 = -INT_MAX, m2 = -INT_MAX;
vector<vector<int>>G;
vector<int>dim;
bitset<100005>discovered;


void BFS(int nod)
{
    queue<int>Q;
    Q.push(nod);
    dim[nod] = 1;
    discovered[nod] = true;
    while(!Q.empty())
    {
        int k = Q.front(); Q.pop();
        for (auto v:G[k])
            if (!discovered[v])
            {
                discovered[v] = true;
                dim[v] = dim[k] + 1;
                if (dim[v] > m1)
                    m1 = dim[v], nod1 = v;
                Q.push(v);
            }
    }
}

int main()
{
    fin >> N;
    G.resize(N + 1);
    dim.resize(N + 1);

    int k = 1;
    for(int i ,j; k < N; ++k)
    {
        fin >> i >> j;
        G[i].push_back(j);
        G[j].push_back(i);
    }
    BFS(1);
    discovered.reset();
    BFS(nod1);
    m1 = -INT_MAX;
    fout << dim[nod1];
    return 0;
}