#include <bits/stdc++.h>

using namespace std;

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

vector <int> g[100005];
int used[100005];
int last_nod=0, maxi_dist=0;

void dfs (int nod) {
    for (int vecin : g[nod]) {
        if (!used[vecin]) {
            used[vecin]=used[nod]+1;
            if (used[vecin]>maxi_dist) {
                maxi_dist=used[vecin];
                last_nod=vecin;
            }
            dfs(vecin);
        }
    }
}

int main()
{
    fin.tie(0); fin.sync_with_stdio(false);
    int n, x, y; fin>>n;
    for (int i=1; i<n; i++) {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    used[1]=1;
    dfs(1);

    for (int i=1; i<=n; i++) used[i]=0;

    //cout<<last_nod<<' ';
    used[last_nod]=1;
    dfs(last_nod);
    //cout<<last_nod;
    fout<<maxi_dist;
    return 0;
}