Ways to Decode

A message containing letters from A-Z is being encoded to numbers using the following mapping:

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

Given an encoded message A containing digits, determine the total number of ways to decode it modulo 10⁹ + 7.

1 <= |A| <= 10⁵

The first and the only argument is a string A.

Return a single integer denoting the total number of ways to decode it modulo 10⁹ + 7.

Input 1:

 A = "8"

Input 2:

 A = "12"

Output 1:

 1

Output 2:

 2

Explanation 1:

 Given encoded message "8", it could be decoded as only "H" (8).
 The number of ways decoding "8" is 1.

Explanation 2:

 Given encoded message "12", it could be decoded as "AB" (1, 2) or "L" (12).
 The number of ways decoding "12" is 2.