#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];
queue<int> q;
struct elem {int n, d;};
queue<elem> p;
 
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);
	for(;!q.empty();q.pop())
		for(auto i : g[q.front()])
			if(!f[i])
				f[i] = 1,
				q.push(i),
				s = i;
 
	memset(f, 0, sizeof(f));
 
	p.push({s, 1});
	for(;!p.empty();p.pop())
		for(auto i : g[p.front().n])
			if(!f[i])
				f[i] = 1,
				p.push({i, p.front().d + 1}),
				l = p.front().d + 1;
 
	out << l;
	return 0;
}