Face Detection

题意翻译

求n*m的方阵中包含face四个字母的正方形个数。

题目描述

The developers of Looksery have to write an efficient algorithm that detects faces on a picture. Unfortunately, they are currently busy preparing a contest for you, so you will have to do it for them. In this problem an image is a rectangular table that consists of lowercase Latin letters. A face on the image is a $ 2×2 $ square, such that from the four letters of this square you can make word "face". You need to write a program that determines the number of faces on the image. The squares that correspond to the faces can overlap.

输入输出格式

输入格式

The first line contains two space-separated integers, $ n $ and $ m $ ( $ 1<=n,m<=50 $ ) — the height and the width of the image, respectively. Next $ n $ lines define the image. Each line contains $ m $ lowercase Latin letters.

输出格式

In the single line print the number of faces on the image.

输入输出样例

输入样例 #1

4 4
xxxx
xfax
xcex
xxxx

输出样例 #1

1

输入样例 #2

4 2
xx
cf
ae
xx

输出样例 #2

1

输入样例 #3

2 3
fac
cef

输出样例 #3

2

输入样例 #4

1 4
face

输出样例 #4

0

说明

In the first sample the image contains a single face, located in a square with the upper left corner at the second line and the second column: In the second sample the image also contains exactly one face, its upper left corner is at the second row and the first column. In the third sample two faces are shown: In the fourth sample the image has no faces on it.