import re

S = input()
k = 100000000000000000000

ans = re.findall("[c]+[^w]*[w]+[^w]*[w]",S)
flg = 0
if ans == []:
    print("-1")
    flg = 1
else:
    for i in ans:
        if len(i) < k:
            k = len(i)

if flg == 0:
    print(k)