# 99 Elm Problems/Problem 63

Construct a complete binary tree.

A complete binary tree with height H is defined as follows:

The levels 1,2,3,...,H-1 contain the maximum number of nodes.

In level H, which may contain less than the maximum possible number of nodes, all the nodes are "left-adjusted". This means that in a level-order tree traversal all internal nodes come first, the leaves come second, and empty successors come last.

**# # # THIS IS A STUB # # #**

Example in Elm:

```
import Html exposing (text)
import List
f : Int -> Int
-- your implementation goes here
main = text (toString (f 0))
```

Result:

```
4
```