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.
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.
def face_detection():
  n, k = map(int, input().split())
  arr = []
  if n == 1:
    print(0)
    return
  for i in range(n):
    arr.append(list(input()))
  count = 0
  m = [[False] * k] * n
  for i in range(n - 1):
    for j in range(k - 1):
      l = arr[i][j] + arr[i + 1][j] + arr[i][j + 1] + arr[i + 1][j + 1]
      l = ''.join(sorted(l))
      if l == 'acef' and (
              m[i][j] & m[i + 1][j] & m[i][j + 1] & m[i + 1][j + 1] == False):
        m[i][j] = True
        m[i + 1][j] = True
        m[i][j + 1] = True
        m[i + 1][j + 1] = True
        count += 1
  print(count)


if __name__ == '__main__':
  face_detection()
