Create Tree
let root = newNode ( 27 ) ; root . left = newNode ( 9 ) ; root . right = newNode ( 81 ) ; root . left . left = newNode ( 3 ) ; root . left . right = newNode ( 10 ) ; root . right . left = newNode ( 70 ) ; root . right . right = newNode ( 243 ) ; root . right . right . left = newNode ( 81 ) ; root . right . right . right = newNode ( 909 ) ;