输入为一行,由若干个单词和句号组成
输出格式参见样例。
A blockhouse is a small castle that has four openings through which to shoot.
a:2 blockhouse:1 castle:1 four:1 has:1 is:1 openings:1 shoot:1 small:1 that:1 through:1 to:1 which:1