StringChallenge(str) takes the str parameter and encodes the message according to the following rule: encode every letter into its corresponding numbered position in the alphabet. Symbols and spaces will also be used in the input. For example, if str is "af5c a#!" then your program should return 16531#!.
Examples:
Input: hello 45
Output: 85121215 45
Input: "jaj-a"
Output: 10110-1