#include <bits/stdc++.h>

using namespace std;

ifstream in("darb.in");
ofstream out("darb.out");
const int NMAX = 100005;
vector<int> v[NMAX];
int dist[NMAX];
int d,last;
void dfs(int b, int u)
{
    dist[b] = 1+dist[u];
    if (dist[b]>d)
    {
        d = dist[b];
        last = b;
    }
    for (auto it: v[b])
        if (!dist[it])
            dfs(it,b);
}

int main()
{
    int n;
    in >> n;
    for (int i = 1; i<n; i++)
    {
        int x,y;
        in >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0);
    memset(dist,0,sizeof(dist));
    dfs(last,0);
    out << d;
}