Book Order Consolidation

You are given several book orders. Each order is provided on a separate line with the format <book_title> <number_of_copies>. The input is terminated by a line containing a single 0.

Your task is to consolidate the orders by summing up the number of copies for each book title and then output the result sorted in alphabetical order by the book title.

In mathematical terms, if a book T is ordered multiple times with counts c₁, c₂, ..., c_k, then the total number of copies for T is given by $$Total = \sum_{i=1}^{k} c_i.$$

If any order does not conform to the expected format, your program should raise an error.

inputFormat

Input is provided via standard input (stdin). Each line represents an order in the format <book_title> <number_of_copies>. The input ends with a line containing only a single 0.

outputFormat

For each unique book title, output a line to standard output (stdout) in the format <book_title>: <total_copies>, where total_copies is the sum of copies for that title. The output must be sorted alphabetically by book title.## sample

HarryPotter 10
0

HarryPotter: 10