S = input()
len_cww = []
start = 0

while True:  
  pos_c = (S[(start):].find("c")) 
  pos_w1 = (S[(pos_c + start + 1):].find("w")) + pos_c + 1
  pos_w2 = (S[(pos_w1 + start + 1):].find("w")) + pos_w1 + 1    

  if (pos_c >= 0) and (pos_w1 != pos_c) and (pos_w1 != pos_w2):
    len_cww.append(pos_w2 - pos_c + 1)
    start += pos_c + 1
  else:
    break

if len(len_cww) == 0:
  print(-1)
else:  
  print(min(len_cww))