s = input()
s += 'x'
l = []
count = 0
temp = ''
min = 101
for i in range(len(s)):
  count = 0
  temp = ''
  if s[i] == 'c':
    for j in range(i, len(s)):
      temp += s[j]
      if s[j] == 'w':
        count += 1

      if count == 2:
        break
    l.append(temp)

for i in l:
  if i.count('w') == 2 and len(i) < min:
    min = len(i)

if not min == 101:
  print(min)
else:
  print(-1)