#include <iostream>
#include <cstdio>
#include <vector>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <fstream>
using namespace std;

int n, x, d[100010];
vector<int> gr[100010];
queue<int> q;

int bfs(int s) {
	int y;
	d[s] = 1;
	q.push(s);
	while (q.size()){
		x = q.front();
		q.pop();
		for (int i = 0; i < gr[x].size(); i++) {
			y = gr[x][i];
			if (!d[y]) {
				d[y] = d[x] + 1;
				q.push(y);
			}
		}
	}
	x = s;
	for (int i = 1; i <= n; i++)
		if (d[i] > d[x]) x = i;
	return x;
}

int main() {
	int x, y;
	
	freopen("darb.in","r",stdin);
	freopen("darb.out","w",stdout);
	scanf("%d", &n);
	for (int i = 1; i < n; i++) {
		scanf("%d %d", &x, &y);
		gr[x].push_back(y);
		gr[y].push_back(x);
	}
	x = bfs(1);
	memset(d, 0, sizeof(d));
	x = bfs(x);
	
	printf("%d\n", d[x]);

	return 0;
}