#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

constexpr const int NMAX = 1e5 + 5;

using namespace std;

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

vector < int > g[NMAX];
bool viz[NMAX];
int dist[NMAX];
int n;

pair <int, int> bfs(int nod){
	viz[0] = !viz[0];
	queue < int > q;
	q.push(nod);
	dist[nod] = 1;
	viz[nod] = viz[0];
	while(!q.empty()){
		nod = q.front();
		q.pop();
		for(int i : g[nod])
			if(viz[i] != viz[0]){
				q.push(i);
				viz[i] = viz[0];
				dist[i] = dist[nod] + 1;
			}
	}
	return {nod, dist[nod]};
}

int main(){
	fin >> n;
	for(int i = 1, x, y; i < n; i++){
		fin >> x >> y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	fin.close();
	fout << bfs(bfs(1).first).second << '\n';
	fout.close();
	return 0;
}