# Grains

Calculate the number of grains of wheat on a chessboard given that the number
on each square doubles.

There once was a wise servant who saved the life of a prince. The king
promised to pay whatever the servant could dream up. Knowing that the
king loved chess, the servant told the king he would like to have grains
of wheat. One grain on the first square of a chess board. Two grains on
the next. Four on the third, and so on.

There are 64 squares on a chessboard.

Write code that shows:
- how many grains were on each square, and
- the total number of grains

## For bonus points

Did you get the tests passing and the code clean? If you want to, these
are some additional things you could try:

- Optimize for speed.
- Optimize for readability.

Then please share your thoughts in a comment on the submission. Did this
experiment make the code better? Worse? Did you learn anything from it?

## Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
`raise Exception`, you shold write:

```python
raise Exception("Meaningful message indicating the source of the error")
```


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For example, if you're submitting `bob.py` for the Bob exercise, the submit command would be something like `exercism submit <path_to_exercism_dir>/python/bob/bob.py`.

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## Source

JavaRanch Cattle Drive, exercise 6 [http://www.javaranch.com/grains.jsp](http://www.javaranch.com/grains.jsp)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.