Write Python code that validates a string.

Your program should:

1. Read a string text from the user.
2. Loops through the characters of text:
   • Check if all non-space (" ") characters are alphabet characters (a to z, A to Z)
     • If all are valid, display "The input is valid"
     • Otherwise, display "The input is invalid"
     • no built-in functions to test characters types like isalpha(), isspace()