#include<fstream>
#include<vector>
using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");

const int nmax = 100006;
int n, dmax, nodmax;
vector<int> vecini[nmax];
bool viz[nmax];

void dfs(int x, int dist)
{
	viz[x] = 1;
	if(dist>dmax)
	{
		nodmax = x;
		dmax = dist;
	}

	for(int i = 0; i<(int)vecini[x].size(); i++)
	{
		if(viz[vecini[x][i]]==0)
			dfs(vecini[x][i], dist + 1);
	}
}

int main(){
	int player_unu=0;

	in>>n;
	for(int i = 1; i<n; i++)
	{
		int a, b;
		in>>a>>b;

		vecini[a].push_back(b);
		vecini[b].push_back(a);
	}

	dfs(1, 0);

	for(int i = 1; i<=n; i++)
		viz[i] = 0;

	dfs(nodmax, 0);

	out<<dmax + 1<<'\n';

	return player_unu;
}