S = str(input())
i = 0
j = 0
cww = -1

for value in S:
	i += 1
	if value == 'c':
		i = 1
		cww = 0
	elif value == 'w' and cww == 0:
		j += 1
		if j == 2:
			if cww < i:
				cww = i
			i = 0
			j = 0
	
if cww < 1:
	print(-1)
else:
	print(cww)