Title Formatter

You are given a string that may contain excess whitespace. Your task is to format the string as a title following these rules:

• The first letter of each word must be capitalized and the rest of the letters in that word must be in lowercase.
• Words in the output should be separated by a single space.
• Any leading, trailing, or extra spaces between words in the input should be removed so that only one space separates words.
• If the string contains any non-alphabetic characters (other than spaces), output None.

For example, an input of " hello world " should yield "Hello World", while an input of "3 elephants are here" should yield "None".

inputFormat

The input consists of a single line containing a string. This string may have leading, trailing or multiple intermediate spaces.

outputFormat

If the input contains any non-alphabetic characters (excluding spaces), output None (without quotes). Otherwise, output the formatted title string.

    hello world    

Hello World