#coding:utf-8

S=raw_input()
N=len(S)

c_w_w=N+1
for i in range(N):
	if S[i] == 'c':
		cnt=0
		for j in range(i+1,N):
			if S[j] == 'w':
				cnt+=1
			if 2 <= cnt:
				c_w_w=min(c_w_w,j-i+1)
				break
				
if c_w_w != N+1:
	print c_w_w
else:
	print -1