H, W = map(int, input().split())
S = [input() for _ in range(H)]
T = [input() for _ in range(H)]
ok1 = True
for i in range(H):
	for j in range(W):
		if S[i][j] == T[i][j]:
			ok1 = False
ok2 = True
for i in range(H):
	for j in range(W):
		if S[H - 1 - i][W - 1 - i] == T[i][j]:
			ok2 = False
ans = 0
now_prob = 1
for i in range(1, 200):
	if not((i % 2 == 1 and ok1) or (i % 2 == 0 and ok2)):
		continue
	prob = 1 - (2 ** (1 - i))
	ans += now_prob * prob * i
	now_prob -= now_prob * prob
print(ans)