Driver code
let root = null ; root = insert ( root , 50 ) ; root = insert ( root , 29 ) ; root = insert ( root , 59 ) ; root = insert ( root , 19 ) ; root = insert ( root , 53 ) ; root = insert ( root , 556 ) ; root = insert ( root , 56 ) ; root = insert ( root , 94 ) ; root = insert ( root , 13 ) ;