# 最小チワワ問題
str = input()
wCount = 0
ans = 100

for n,sc in enumerate(str):
  wCount=0
  length=1
  if(sc=='c'):
    for sw in str[n+1:]:
      length+=1
      if(sw=='w'):
        wCount+=1
      if(wCount==2):
        if(ans>length):
          ans=length
if(ans==100):
  print(-1)
else:
  print(ans)