import java.io.*;
import java.util.*;

public class Main {
    static ArrayList<ArrayList<Integer>> graph = new ArrayList<>();
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        for (int i = 0; i < n; i++) {
            graph.add(new ArrayList<>());
        }
        for (int i = 0; i < n - 1; i++) {
            int a = sc.nextInt() - 1;
            int b = sc.nextInt() - 1;
            graph.get(a).add(b);
            graph.get(b).add(a);
        }
        check(0, 0);
        System.out.println(-check(0, 0).poll());
    }
    
    static PriorityQueue<Integer> check(int idx, int p) {
        PriorityQueue<Integer> ans = new PriorityQueue<>();
        for (int x : graph.get(idx)) {
            if (x == p) {
                continue;
            }
            ans.addAll(check(x, idx));
        }
        int value = 0;
        if (ans.size() > 0) {
            value += ans.poll();
        }
        if (ans.size() > 0) {
            value += ans.poll();
        }
        value--;
        ans.add(value);
        return ans;
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}