using System;
using System.Collections.Generic;
class Program
    {
        public class Node
        {
            public int id;
            public List<Node> link = new List<Node>();

            public Node(int i)
            {
                id = i;
                link = new List<Node>();
            }
        }

        static void connect (Node a, Node b)
        {
            a.link.Add(b);
            b.link.Add(a);
            return;
        }
    	static void Main(string[] args)
    	{
            int n = int.Parse(Console.ReadLine());
            List<Node> nodes = new List<Node>();
            for (int i=0; i<n; i++) nodes.Add(new Node(i));
            for (int i=0; i<n-1; i++)
            {
                string[] s = Console.ReadLine().Split(' ');
                connect(nodes[int.Parse(s[0]) - 1], nodes[int.Parse(s[1]) - 1]);
            }
            int[] searchList = new int[n];
            for(int i=0; i<n; i++) searchList[i] = -1;
            List<int> queue = new List<int>();
            queue.Add(0);
            searchList[0] = 0;
            int lastId = 0;
            while(queue.Count > 0)
            {
                int id = queue[0];
                foreach(Node node in nodes[id].link)
                {
                    if (searchList[node.id] < 0){
                        searchList[node.id] = searchList[id] + 1;
                        queue.Add(node.id);
                    }
                }
                lastId = id;
                queue.Remove(id);
            }
            //Console.Error.WriteLine(lastId);
            int start = lastId;

            queue.Add(lastId);
            for(int i=0; i<n; i++) searchList[i] = -1;
            searchList[lastId] = 0;
            while(queue.Count > 0)
            {
                int id = queue[0];
                foreach(Node node in nodes[id].link)
                {
                    if (searchList[node.id] < 0){
                        searchList[node.id] = searchList[id] + 1;
                        queue.Add(node.id);
                    }
                }
                lastId = id;
                queue.Remove(id);
            }
            //Console.Error.WriteLine(start +  " " + lastId + " " + searchList[lastId]);
            Console.WriteLine(n - 1 - searchList[lastId]);
            
        }
    }
    //mcs Main.cs
    //mono Main.exe