#include <bitset>
#include <cmath>
#include <algorithm>
#include <numeric>
#include <deque>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#define NMAX 200001
#define MAX 150001
#define pb push_back
#define MOD 1000000007
#define nl '\n'
#define INF 0x3f3f3f3f
#define pii1 pair<int, pair<int,int>>  (1,(1,2));
#define pii pair<int,int>
#define tpl tuple<int,int,int>
#define int long long
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int n,x,y,maxi,aux;
vector<bool>vis(NMAX);
vector<vector<int>>G(NMAX);

void dfs(int node,int dist)
{
    vis[node]=1;
    if(maxi<dist)
    {
        maxi=dist;
        aux=node;
    }

    for(auto x:G[node])
    {
        if(!vis[x])
            dfs(x,dist+1);
    }
}
signed main() {


    fin>>n;
    for(int i=1;i<n;++i)
    {
        fin>>x>>y;
        G[x].pb(y);
        G[y].pb(x);
    }
    dfs(1,1);
    fill(vis.begin(),vis.end(),false);
    dfs(aux,1);
    fout<<maxi;

    return 0;
}