A message containing letters from `A`

to `Z`

is being encoded to numbers using the following mapping:

```
'A' -> 1
'B' -> 2
...
'Z' -> 26
```

Given an encoded message containing digits, determine the total number of ways to decode it.

Example

Given encoded message `12`

, it could be decoded as `AB`

(1, 2) or `L`

(12).
The number of ways decoding `12`

is `2`

.