#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 100000;

int N, nodDiametru, dmax;
vector<int> g[NMAX + 5];

void dfs(int fiu, int tata, int h)
{
    if(h > dmax)
    {
        dmax = h;
        nodDiametru = fiu;
    }
    for(auto it : g[fiu])
    {
        if(it != tata)
        {
            dfs(it, fiu, h + 1);
        }
    }
}

int main()
{
    fin >> N;
    for(int i = 1; i < N; i ++)
    {
        int u, v;
        fin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    dfs(1, 0, 0);
    dmax = 0;
    dfs(nodDiametru, 0, 0);
    fout << 1 + dmax << '\n';
}