Comment removal

Time limit1sMemory limit128 MB

Summary

Strip Pascal comments and collapse whitespace, honoring single-quote strings where doubled quotes are literals and comments can span lines.

Level: Medium6 of 10
Topics: String, Simulation, Implementation, String matching
Solved: No attempts yet

Problem

Given an arbitrary, syntactically correct Pascal program, compress it. (You do not need to know the Pascal programming language to solve this problem; all the information you need is given below.) Apply the following rules to compress the program:

Replace every sequence of blanks, except those inside a string constant, with a single blank. Also remove all blanks at the beginning of a line and all blanks at the end of a line. In Pascal, strings are delimited by single quotes ('). Inside a string, two consecutive single quotes denote one single-quote character. For example:
```
'This is a string'
'isn''t this fun?'
```
A string may not cross a line boundary.
Replace every comment with a single blank. (If this blank ends up next to another blank, the two are compressed as described above.) In Pascal, a comment is enclosed either by (* ... *) or by { ... }, as in:
```
(* This is a comment! *)
{ A comment with a '*)'. }
(* A (* comment *)
```
A comment may span several lines. Comments may not be nested.
Remove every totally blank line, i.e. a line that contains only blanks (either originally, or after the comments have been removed).
The source contains no tab characters and no other non-printing characters (apart from line separators).
No line of the source is longer than 255 characters.

Input

A single, syntactically correct Pascal program is given on standard input. It contains no tab characters and no other non-printing characters (apart from line separators), and no line is longer than 255 characters.

Output

Output the compressed Pascal program obtained by applying the rules above, and nothing else.

Examples1

Example 1

Input

{ The famous 'Hello world' program }

program  Hello  (output):
  (* no declarations *)
begin
  WriteLn('Hello ,  ''quaint'' world !');
end.

Expected output

program Hello (output):
begin
WriteLn('Hello ,  ''quaint'' world !');
end.