import re
s,matcher,patterns,res=input(),"c.*?w.*?w",[],[]
for (i,c) in enumerate(s):
    if c=="c":
        patterns.append(s[i:])
for pattern in patterns:    
    matches=re.findall(matcher,pattern)
    for match in matches:
        res.append(match)
res.sort(key=lambda x:len(x))
if len(res)!=0:
    print(len(res[0]))
else:
    print(-1)