#include <iostream>

int main() {
    std::string s;
    int c = -1, w = -1, flag = 0;
    std::cin >> s;
    for (int i = 0; i < s.length() && c == -1; i++)
        if (s[i] == 'c') c = i;
    for (int i = s.length() - 1; i >= 0  && i > c && c != -1; i--)
        if (s[i] == 'w')
            if (w == -1) w = i;
            else flag = 1;

    std::cout << (flag ? w - c + 1 : -1) << std::endl;
    return 0;
}