# Problem 7

## Description

This problem was asked by Facebook.

Given the mapping `a = 1, b = 2, ... z = 26`

, and an encoded message, count the number of ways it can be decoded.

For example, the message `111`

would give `3`

, since it could be decoded as `aaa`

, `ka`

, and `ak`

.

You can assume that the messages are decodable. For example, `001`

is not allowed.