S = str(input())


chiwawa_index_dict = {"c": 0, "first_w": 0, "second_w": 0}
has_filled_c = False
has_filled_first_w = False
has_filled_second_w = False
for i, word in enumerate(S):
	print(word)
	print(chiwawa_index_dict)
	if word == "c" and not has_filled_c:
		chiwawa_index_dict["c"] = i
		has_filled_c = True
	elif word == "w" and has_filled_c and not has_filled_first_w:
		chiwawa_index_dict["first_w"] = i
		has_filled_first_w = True
	elif word == "w" and has_filled_c and has_filled_first_w and not has_filled_second_w:
		chiwawa_index_dict["second_w"] = i
		has_filled_second_w = True
		break

if has_filled_second_w:
	print(chiwawa_index_dict["second_w"] - chiwawa_index_dict["c"] + 1)
else:
	print(-1)