#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
using namespace std;

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

int n, s, l;
bool f[100001];
vector<int> g[100001];
struct elem {int n, d;};
queue<elem> q;

void read()
{
	in >> n;
	int x, y;
	for(int i = 1; i < n; ++i)
		in >> x >> y,
		g[x].push_back(y),
		g[y].push_back(x);
}

int main()
{
	read();

	q.push({1, 0});
	for(;!q.empty();q.pop())
		for(auto i : g[q.front().n])
			if(!f[i])
				f[i] = 1,
				q.push({i, 0}),
				s = i;

	memset(f+1, 0, n*sizeof(int));

	q.push({s, 1});
	for(;!q.empty();q.pop())
		for(auto i : g[q.front().n])
			if(!f[i])
				f[i] = 1,
				q.push({i, q.front().d + 1}),
				l = q.front().d + 1;

	out << l;
	return 0;
}