欢迎来到起遇信息学
起遇信息学正处于上线筹建阶段,以下功能已全部开放免费体验: ✅ 完整题库浏览与代码提交评测(C / C++ / Python / Java 等) ✅ 入门到进阶的系列课程试读、作业与考试 ✅ AI 提示、AI 作业分析等智能助教功能 ✅ 赛事模拟与个人能力报告 ✅ 邮箱注册开放 ⏳ 付费课程订阅与微信/支付宝支付通道 ⏳ 手机号登录,微信扫码登录、微信公众号绑定 使用中如遇任何问题,欢迎通过页面底部 **"联系我们"** 与我们沟通。
CF1106A.Lunar New Year and Cross Counting
Lunar New Year and Cross Counting
Lunar New Year is approaching, and you bought a matrix with lots of "crosses".
This matrix of size contains only 'X' and '.' (without quotes). The element in the -th row and the -th column is defined as , where . We define a cross appearing in the -th row and the -th column () if and only if $M(i, j) = M(i - 1, j - 1) = M(i - 1, j + 1) = M(i + 1, j - 1) = M(i + 1, j + 1) =$ 'X'.
The following figure illustrates a cross appearing at position in a matrix.
X.X
.X.
X.X
Your task is to find out the number of crosses in the given matrix . Two crosses are different if and only if they appear in different rows or columns.
Input
The first line contains only one positive integer (), denoting the size of the matrix .
The following lines illustrate the matrix . Each line contains exactly characters, each of them is 'X' or '.'. The -th element in the -th line represents , where .
Output
Output a single line containing only one integer number — the number of crosses in the given matrix .
Note
In the first sample, a cross appears at , so the answer is .
In the second sample, no crosses appear since , so the answer is .
In the third sample, crosses appear at , , , , so the answer is .
Samples
5
.....
.XXX.
.XXX.
.XXX.
.....
1
2
XX
XX
0
6
......
X.X.X.
.X.X.X
X.X.X.
.X.X.X
......
4
在线编程 IDE
建议全屏模式获得最佳体验
| 进入全屏编程 | Alt+E |
| 递交评测 | Ctrl+Enter |
| 注释/取消注释 | Ctrl+/ |
| 缩放字体 | Ctrl+滚轮 |