N, M = map(int, input().split())
ans = 0
end = set()
S = [input() for _ in range(N)]
for i in range(M):
	C = []
	for j in range(N):
		if S[j][i] == "o":
			C.append(j)
	
	if len(C) == 1 and C[0] not in end:
		end.add(C[0])
		ans += 1
	else:
	    for c in C:
	        end.add(c)
print(ans)