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

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

vector<int> L[100005];
bitset<100005> v;
int n, m, r;
queue<int> q;
int d[100005];

void BFS(int k)
{
    q.push(k);
    v[k] = 1;
    d[k] = 1;
    while(!q.empty())
    {
        k = q.front();
        q.pop();
        for(auto w : L[k])
            if(v[w] == 0)
            {
                d[w] = d[k] + 1;
                q.push(w);
                v[w] = 1;
            }
    }
}

int main()
{
    int i, x, y;
    fin >> n;
    for(i=1; i<n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    BFS(1);
    int maxi, p;
    maxi = 0;
    for(i=1; i<=n; i++)
    {
        if(d[i] > maxi)
        {
            maxi = d[i];
            p = i;
        }
        d[i] = 0;
    }
    v.reset();
    BFS(p);
    for(i=1; i<=n; i++)
        if(d[i] > maxi) maxi = d[i];
    fout << maxi;
    fin.close();
    fout.close();
    return 0;
}