Normalize Sentences

You are given a text string that may contain multiple sentences. Each sentence is defined as a string ending with one of the punctuation marks: . ! ?. Your task is to write a program that normalizes the text by ensuring the following:

• Each sentence starts with a capital letter.
• Each sentence ends with a single period (.).
• Any extraneous whitespace is removed.
• Any punctuation characters (other than the sentence-ending ones) are removed from the sentence.

If the input is not a valid string, the program should output undefined (as a string). In addition, if a sentence does not already end with a punctuation mark, append a period at the end.

The normalization for each sentence can be described mathematically by the formula:

$$\text{NormalizedSentence} = Capitalize(\text{Trim}(\text{RemoveExtraSpaces}(\text{RemovePunctuation}(sentence))) )$$

Output the complete normalized text where sentences are separated by a period and a space.

inputFormat

The input consists of a single text string provided via standard input (stdin). The string may include newline characters and irregular spacing.

outputFormat

The output should be a single normalized string printed to standard output (stdout) following the rules described above.

## sample

this is a sentence!   here is another one? and here's a third sentence. multiple lines, irregular spacing!

This is a sentence. Here is another one. And heres a third sentence. Multiple lines irregular spacing.