A receipt has been mangled into a single string with letters and digits mixed together. Given s, return the sum of every digit character that appears in it (each digit counted on its own, so "42" contributes 4 + 2).
Examples
Input: s = "a1b2c3"
Output: 6
Input: s = "Room 305, floor 12"
Output: 11
Constraints
0 <= len(s) <= 5000smay contain letters, digits, spaces and punctuation
Goals
- Recognise digit characters with `isdigit`
- Convert a character to an integer
- Accumulate a total