dojo2021.py

#!/usr/bin/env python
# Python 3.9.5

W, H = [ int(x) for x in input().split(" ") ]

MAP = []
start_w = 0
start_h = 0

for i in range(H):
    row = list(input())
    MAP.append(row)
    for j, value in enumerate(row):
        if value == "@":
            start_w = j
            start_h = i

def dfs(w, h):
    count = 0

    if MAP[h][w] == "#":
        return 0
    else:
        count += 1

    MAP[h][w] = "#"
    
    if w != 0:
        count += dfs(w-1, h)
    
    if w != W - 1:
        count += dfs(w+1, h)

    if h != 0:
        count += dfs(w, h-1)
    
    if h != H - 1:
        count += dfs(w, h+1)
    
    return count

print(dfs(start_w, start_h))