Problem:
Book Index

Books are indexed. Write a program which reads a list of pairs of a word and a page number, and prints the word and a list of the corresponding page numbers.

You can assume that a word consists of at most 30 characters, and the page number is less than or equal to 1000. The number of pairs of a word and a page number is less than or equal to 100. A word never appear in a page more than once.

The words should be printed in alphabetical order and the page numbers should be printed in ascending order.

Input

word page_number
:
:

Output

word
a_list_of_the_page_number
word
a_list_of_the_Page_number
:
:

Sample Input

style 12
even 25
introduction 3
easy 9
style 7
document 13
style 21
even 18

Output for the Sample Input

document
13
easy
9
even
18 25
introduction
3
style
7 12 21

Solution in Ruby (judge verdict: Accepted)

indice = {}
while page_info = gets
  break if page_info.nil? || page_info.empty?
  page_contents, page_number = page_info.strip.split
  indice[page_contents] = [] unless indice.has_key?(page_contents)
  indice[page_contents] << page_number.to_i
end

indice.sort{ |(k1, v1), (k2, v2)| k1 <=> k2 }.each do |word, page_numbers|
  puts word
  puts page_numbers.sort.join(" ")
end