letterlst = ['c', 'w', 'w']
S = raw_input()
min = len(S)+1
for i in range(0, len(S)):
	cnt = 0
	flag = 0
	for j in range(i, len(S)):
		if flag != 0: cnt += 1
		if S[j] == letterlst[flag]:
			if flag == 0: cnt = 1
			flag += 1
		if flag == 3: break
	if cnt < min: min = cnt
if min == len(S)+1: print -1
else: print min