import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<ArrayList<Integer>> graph = new ArrayList<>();
		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);
		}
		PriorityQueue<Path> queue = new PriorityQueue<>();
		int[] costs = new int[n];
		queue.add(new Path(0, 0));
		search(graph, queue, costs);
		int max = 0;
		int maxIdx = 0;
		for (int i = 0; i < n; i++) {
		    if (max < costs[i]) {
		        max = costs[i];
		        maxIdx = i;
		    }
		}
		queue.add(new Path(maxIdx, 0));
		search(graph, queue, costs);
		Arrays.sort(costs);
		System.out.println(n - costs[n - 1] - 1);
	}
	
	static void search(ArrayList<ArrayList<Integer>> graph, PriorityQueue<Path> queue, int[] costs) {
	    Arrays.fill(costs, Integer.MAX_VALUE);
	    while (queue.size() > 0) {
	        Path p = queue.poll();
	        if (costs[p.idx] <= p.value) {
	            continue;
	        }
	        costs[p.idx] = p.value;
	        for (int x : graph.get(p.idx)) {
	            queue.add(new Path(x, p.value + 1));
	        }
	    }
	}
	
	static class Path implements Comparable<Path> {
	    int idx;
	    int value;
	    
	    public Path(int idx, int value) {
	        this.idx = idx;
	        this.value = value;
	    }
	    
	    public int compareTo(Path another) {
	        return value - another.value;
	    }
	}
}