S = list(raw_input())
N = len(S)
ans = N+1
for i in xrange(N-2):
	for j in xrange(i+1,N-1):
		for k in xrange(j+1,N):
			if S[i]=="c" and S[j]=="w" and S[k] == "w":
				ans = min(k-i+1,ans)
print -1 if ans > N else ans