Can You Solve This Using Only Chapter 1?

Here’s a problem I recently gave my students. Can you solve it using only Chapter 1 of Learn to Code by Solving Problems?

Fix Dan’s Sentences

Dan’s writing a new book, but he needs a bit of help with his grammar. Correct the given sentences by adding commas in the correct locations throughout the sentence.

Input

• A single line containing the sentence to be fixed. A sentence is composed of exactly two words, then one or more nouns (each of which may or may not already have a comma after it), then an and (which will not occur anywhere else in the sentence), then one more word followed by a period. Words consist only of lowercase or uppercase letters.
• The input has no leading or trailing spaces.
• Any two consecutive words are separated by exactly one space (see examples below).

For example, the sentence Dinner is chocolate, goldfish and mustard. is a valid input, and so is TAs like code exams tests essays and grading.

Output

Output the sentence with one comma after each noun (nouns in this problem are the words indicated above in the input section). Do not add or modify anything else about the given sentence.

For example, given the input TAs like code exams tests essays and grading. , your code should output TAs like code, exams, tests, essays, and grading.

Requirements

• You MUST use the string method replace to solve this problem (i.e. no lists, split, or anything else after Chapter 1).
• Using if-statements or loops of any kind is not allowed.

Sample Input 1

Ruth eats apples oranges, kiwis and bananas.

Sample Output 1

Ruth eats apples, oranges, kiwis, and bananas.

Sample Input 2

Parvati reads books and code.

Sample Output 2

Parvati reads books, and code.