fn main() {
    println!("Hello, world!");
}

struct Solution {}

// Definition for a binary tree node.
#[derive(Debug, PartialEq, Eq)]
pub struct TreeNode {
  pub val: i32,
  pub left: Option<Rc<RefCell<TreeNode>>>,
  pub right: Option<Rc<RefCell<TreeNode>>>,
}

impl TreeNode {
  #[inline]
  pub fn new(val: i32) -> Self {
    TreeNode {
      val,
      left: None,
      right: None
    }
  }
}
use std::rc::Rc;
use std::cell::RefCell;
impl Solution {
    pub fn increasing_bst(root: Option<Rc<RefCell<TreeNode>>>) -> Option<Rc<RefCell<TreeNode>>> {
        match root.unwrap().get_mut() {
            TreeNode { val, left: None, right: None } => {root}
        }
    }
}