h, w = map(int, input().split())
S = []
flag = True
for i in range(h):
    r = list(input())
    S.append(r)
for i in range(0,h-1):
    for j in range(0,w-1):
        if S[i][j]=='#' and S[i-1][j]=='.' and S[i][j-1]=='.' and S[i+1][j]=='.' and S[i][j+1]=='.':
            flag = False
print(flag)