Book Search

You are given a search query and an optional author name. Your task is to simulate a book search in a predefined database. The database contains the following two books:

• Harry Potter and the Philosopher's Stone by J.K. Rowling, published in 1997.
• Harry Potter and the Chamber of Secrets by J.K. Rowling, published in 1998.

The program should read input from stdin and write output to stdout. If the search query is empty, the program must output an error message. Otherwise, the program should print the details of all books (one per line) in the following format:

title,author,published_year

Note that the search behavior is simulated: regardless of the provided author name, if the query is non-empty, the fixed list of books is returned.

Formally, let \( Q \) be the query string. The program should satisfy: \[ \text{if } Q = \varepsilon, \text{ then output } "Error: The search query must not be empty."; \] Otherwise, output the fixed list of books.

inputFormat

The input consists of two lines:

1. The first line contains the search query (a non-empty string).
2. The second line contains the author name. This line may be empty; if empty, only the query is used for the search.

All input is read from stdin.

outputFormat

If the search query is empty, output Error: The search query must not be empty. (followed by a newline). Otherwise, output the details of the books, one per line, in the following format:

title,author,published_year

The output should be written to stdout.

## sample

Harry Potter
J.K. Rowling

Harry Potter and the Philosopher's Stone,J.K. Rowling,1997
Harry Potter and the Chamber of Secrets,J.K. Rowling,1998

</p>