var assert = require('assert');

​

function Node(val) {

  this.val = val;

  this.left = this.right = null;

}

​

function bottomLeftNodeVal(root) {

  // Fill in this method

  return root;

}

​

// const root = new Node(4);

// root.left = new Node(1);

// root.right = new Node(3);

// root.right.left = new Node(5);

// root.right.right = new Node(9);

​

// console.log(bottomLeftNodeVal(root));

​

function Node(val) {

  this.val = val;

  this.left = null;

  this.right = null;

}

​

// Regular binary trees