#include <fstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <unordered_map>
#include <cstring>
#include <climits>

#define NMAX 2000003
using namespace std;

int n,maxim=0,ult=0;
bool viz[100001];
vector<int>graf[100001];

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

void dfs(int nod,int k)
{
	viz[nod] = true;
	for (int i = 0; i < graf[nod].size(); i++)
	{
		int val = graf[nod][i];
		if (!viz[val])
		{
			if (maxim <= k + 1)
			{
				maxim = k + 1;
				ult = val;
			}
			dfs(val, k + 1);
		}
	}
}

int main()
{
	fin >> n;
	for (int i = 1; i < n ; i++)
	{
		int x, y;
		fin >> x >> y;
		graf[x].push_back(y);
		graf[y].push_back(x);
	}
	dfs(1,1);
	memset(viz, 0, 100001);

	dfs(ult, 1);
	fout << maxim;
	return 0;
}