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.
import sys

def main():
    # fin = open("input.txt", "r")
    fin = sys.stdin
    
    n, m = map(int, fin.readline().split())
    A = []
    for i in range(n):
        A.append(fin.readline().rstrip())

    cnt = 0
    for i in range(n - 1):
        for j in range(m - 1):
            S = {A[i][j], A[i][j + 1], A[i + 1][j], A[i + 1][j + 1]}
            if ("f" in S) and ("a" in S) and ("c" in S) and ("e" in S):
                cnt += 1

    print(cnt)

    fin.close()

main()