英语角
Power English让制作一个程序，统计成员学习的单词个数，你能帮他们吗？
Input
输入为一篇英语文章，为了简单，测试数据保证文章中只包含单词和数字
Output
按照字典序输出文章中的单词，当然重复的只输出一次，每两个单词之间一个空格，最后换行输出去重后单词数目
Sample Input
Five of the notes have two two two alternate equals sign Thus there are are are
Sample Output
</p>Five Thus alternate are equals have notes of sign the there two
12