# -*- coding: utf-8 -*-

s = list(input())
minlen = 999999
length = 999999

for i in range(len(s)):
    if s[i] == "c":
        t = s[i+1:len(s)]
        try:
            t.remove("w")
        except:
            pass
        try:
            if "w" in t:
                length = t.index("w") + 3
        except:
            pass
        minlen = min(minlen,length)

if minlen == 999999:
    minlen = -1

print(minlen)