static class Node {
        Node left;
        Node right;
        int data;
        public Node(){}
        public Node(int data) {
            this.data = data;
        }
    }
    
    public static Node insert(Node root,int data) {
        Node n = new Node(data);
        Node head = root;
        if (root == null) {
            root = n;
        }
        while (head != null) {
            if (data < head.data && head.left == null) {
                head.left = n;
                break;
            } else if (data < head.data && head.left != null) {
                head = head.left;
            } else if (data >= head.data && head.right != null) {
                head = head.right;
            } else if (data >= head.data && head.right == null) {
                head.right = n;
                break;
            }
        }
        return root;
    }

    public static void main(String[] args) throws IOException {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

			  // Not really used, this is the num of elements to be inserted
        int size = Integer.parseInt(bufferedReader.readLine().trim());

        List<Integer> tree = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
            .map(Integer::parseInt)
            .collect(toList());
        
        Node root = insert(null, tree.get(0));
        
        for (int i = 1; i < tree.size(); i++) {
            root = insert(root, tree.get(i));
        }
        /*
        printPreOrder(root, bufferedWriter);
        bufferedWriter.newLine();
        */
				
        // Here is where the logic must be placed...
        int height = getHeight(root);
        bufferedWriter.write(String.valueOf(height));
        
        bufferedReader.close();
        bufferedWriter.close();
    }

public static int height(Node root) {
        if(root==null){
        return -1;
        }

        int left = height(root.left);
        int right = height(root.right);

        return Math.max(left, right)+1;
}

def height(root, prev=0):
    return max(height(root.left), height(root.right))+1 if root is not None and (root.left is not None or root.right is not None) else prev
`