#!/usr/bin/env python
# -*- coding:utf-8 -*-

import re


def chiwawa(S):
    pattern = re.compile("c[^cw]*w[^cw]*w")
    chiwawa = pattern.search(S)

    if chiwawa is None:
        return -1
    else:
        return len(chiwawa.group(0))


def main():
    S = input()
    print(chiwawa(S))


if __name__ == '__main__':
    main()