s = raw_input()
ans = 10000
for i in range(len(s)):
	if s[i] == 'c':
		for j in range(i + 1,len(s)):
			if s[j] == 'w':
				for k in range(j + 1,len(s)):
					if s[k] == 'w':
						ans = min(ans,k - i + 1)
if ans == 10000:
	print -1
else :
	print ans