#include <bits/stdc++.h>

using namespace std;

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

int n, m, x, y, viz[100100];
vector<int> v[100100];

void dfs(int f, int lvl) {
	viz[x] = 1;
	if (lvl > y) {
		y = lvl;
		x = f;
	}
	for (auto g : v[f])
		if (!viz[g])
			dfs(g, lvl + 1);
}

int main() {
	in >> n;
	for (int i = 1; i < n; i++) {
		in >> x >> y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	
	y = 0;
	dfs(1, 1);
	memset(viz, 0, sizeof viz);
	y = 0;
	dfs(x, 1);
	
	out << y - 1;
	return 0;
}