s = input()

wnum = 0
w1idx = 0
cww = 0
res = len(s) + 1
for i,ss in enumerate(reversed(s)):
  if wnum >= 1:
    cww += 1

  if wnum == 0:
    if ss == 'w':
      wnum = 1
      cww = 1
  elif wnum == 1:
    if ss == 'w':
      wnum += 1
      w1idx = i
  elif wnum == 2:
    if ss == 'c':
      res = min(cww, res)
      wnum = 1
      cww = i - w1idx + 1
      w1idx = 0
    elif ss == 'w':
      w1idx = i
      cww = i - w1idx + 1
if res > len(s):
  res = -1

print(res)