CF147A.Punctuation

You are given a text that consists of lowercase Latin letters, spaces and punctuation marks (dot, comma, exclamation mark and question mark). A word is defined as a sequence of consecutive Latin letters.

Your task is to add spaces to the text by the following rules:

• if there is no punctuation mark between two words, then they should be separated by exactly one space
• there should be no spaces before each punctuation mark
• there should be exactly one space after each punctuation mark

It is guaranteed that there is at least one word between any two punctuation marks. The text begins and ends with a Latin letter.

给定一段文本，其中只包含小写拉丁字母、空格以及标点符号（句号、逗号、感叹号和问号）。单词被定义为连续的拉丁字母序列。

你的任务是按照以下规则向文本中添加空格：

• 若两个单词之间没有标点符号，则它们之间应恰好有一个空格；
• 每个标点符号前面不能有空格；
• 每个标点符号后面应恰好有一个空格。

保证任意两个标点符号之间至少存在一个单词。文本以拉丁字母开头，也以拉丁字母结尾。

The input data contains of a single non-empty line — the text whose length is no more than 10000 characters.

输入数据包含一行非空文本，其长度不超过 10000 个字符。

Print the text, edited according to the rules. In this problem you should follow the output format very strictly. For example, extra space at the end of the output line is considered as wrong answer. Note that a newline character at the end of the line doesn't matter.

按照规则编辑文本并输出。本题中，您必须严格遵循输出格式。例如，输出行末尾的多余空格将被视为错误答案。注意，行末的换行符不影响答案正确性。