Binary tree implementation

import java.util.concurrent.ThreadLocalRandom;
import static java.lang.System.out;

final class Main {
    public static void main(String[] args) {
        var root = new Node(10);
        for (int i = 0; i < 10; i++) {
            root.add(new Node(ThreadLocalRandom.current().nextInt(20)));
        }
        out.println(new BinaryTree(root).size());
    }
}