def w(s):
  l=set()
  m=[]
  f=s.find('c')
  if f<0:return -1
  if s[f+1:].count('w')<2:return -1
  for i in range(f,len(s)-1):
    if s[i:].count('w')<2:break
    b=s.find('w',i+1)
    c=s.find('w',b+1)
    a=s[:b].rfind('c')
    l.add(s[a:c+1])
  if '' in l:
    l.remove('')
  return min([len(x) for x in l])

print(w(input()))