# coding=utf-8:

import re

s = str(input())
if "cww" in s:
    print(3)
elif "cww" not in s:
    print(-1)
elif len(s) < 3:
    print(-1)
elif len(s) >= 4:
    c = re.compile(r'.*c.*w.*w')
    countList = list()
    for i in range(len(s)):
        temp1 = re.search(c, s[i:])
        if temp1 != None:
            temp2 = temp1.group()
            countList.append(len(temp2))
        else:
            break
    print(min(countList))