with open("day4/input.txt") as file:
    paperrolls = [str(line.strip("\n")) for line in file.readlines()]


h = len(paperrolls)
w = len(paperrolls[0]) if h>0 else 0

dirs = [(-1,-1),(-1,0),(-1,1),(0,-1),(0,1),(1,-1),(1,0),(1,1)]

def neighbors_count(r,c):
    cnt = 0
    for dr,dc in dirs:
        rr,cc = r+dr, c+dc
        if 0 <= rr < h and 0 <= cc < w and paperrolls[rr][cc] == '@':
            cnt += 1
    return cnt

accessible = 0
for r in range(h):
    for c in range(w):
        if paperrolls[r][c] == '@' and neighbors_count(r,c) < 4:
            accessible += 1

print(accessible)