import sequtils,strutils
var
    W,H : int
    C = newSeq[string](0)
    cnt : int
    D = [[0, 1], [1, 0], [-1, 0], [0, -1]]
    flag : array[21, array[21, bool]]
(W, H) = stdin.readline.split.map(parseInt)
for h in 1..H:
    C.add(stdin.readline)
    
proc tansakuA(px, py : int)=
    C[py][px] = chr(cnt + ord('0'))
    for d in D:
        var (ny, nx) = (py + d[1], px + d[0])
        if ny >= H or ny < 0:
            continue
        if nx >= W or nx < 0:
            continue
        if flag[ny][nx] == true or C[ny][nx] == '#':
            continue
        flag[ny][nx] = true
        tansakuA(nx, ny)
        flag[ny][nx] = false
        
    
for i in 0..<H:
    for j in 0..<W:
        if C[i][j] == '.':
            flag[i][j] = true
            tansakuA(j, i)
            cnt += 1
cnt = 1
block tansaku:
    while true:
        for i in 0..<H:
            for j in 0..<W:
                if C[i][j] == chr(cnt + ord('0')):
                    for d in D:
                        var (ny, nx) = (i + d[1], j + d[0])
                        if ny < 0 or ny >= H:
                            continue
                        if nx < 0 or nx >= W:
                            continue
                        if C[ny][nx] == '#':
                            C[ny][nx] = char(cnt + 1 + ord('0'))
                        elif C[ny][nx] == '0':
                            echo cnt - 1
                            break tansaku
        cnt += 1