#include <bits/stdc++.h>
#define pb push_back
#define int long long
using namespace std;
const int N=1e5+5;
vector<int> g[N];
pair<int,int> dfs(int node, int tata=0, int dep=0)
{
    pair<int,int> mx={dep,node};
    for(auto x:g[node])
    {
        if(x==tata) continue;
        mx=max(mx,dfs(x,node,dep+1));
    }
    return mx;
}
signed main()
{
    ifstream cin("darb.in");ofstream cout("darb.out");
    int n;
    cin>>n;
    for(int _=1;_<n;++_)
    {
        int u,v;cin>>u>>v;
        g[u].pb(v);
        g[v].pb(u);
    }
    pair<int,int> a=dfs(1);
    pair<int,int> b=dfs(a.second);
    cout<<b.first+1;
}