import re

def main():
    s = input()
    m = re.search(r"c.*?w.*?w", s)
    ans = 101
    while m != None:
        ans = min(ans, len(m.group(0)))
        m = re.search(r"c.*?w.*?w", s[m.endpos:])
    if (ans == 101):
        ans = -1
    print(ans)

main()