#!/usr/bin/env python3

import itertools


def len_of_shortest_cww_str(s):
    g = itertools.combinations(range(len(s)), 3)
    res = min((k - i + 1 for i, j, k in g
               if s[i] == "c" and s[j] == s[k] == "w"),
              default=-1)
    return res


def main():
    print(len_of_shortest_cww_str(input()))


if __name__ == '__main__':
    main()