import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

S = np.array(list(read().decode('utf-8').rstrip()),'U1')

L = len(S)
INF = 10 ** 9
left_c = np.full(L,-INF,np.int32)
left_c[1:] = np.where(S[:-1] == 'c',np.arange(L-1),-INF)
np.maximum.accumulate(left_c,out=left_c)

L = len(S)
right_w = np.full(L,INF,np.int32)
right_w[:-1] = np.where(S[1:] == 'w',np.arange(1,L),INF)
right_w = np.minimum.accumulate(right_w[::-1])[::-1]

x = right_w - left_c + 1
x[S!='w'] = INF

answer = x.min()
if answer > L:
    answer = -1
print(answer)