// No.345 最小チワワ問題
// https://yukicoder.me/problems/no/345
//
using namespace std;

#include <iostream>
#include <regex>

long solve(string &S);

int main() {
    string S;
    cin >> S;
    long ans = solve(S);
    cout << ans << endl;
}


long solve(string &S) {
    const long NOT_FOUND = 9999999;
    long min_size = NOT_FOUND;
    regex rx(R"(c.*w.*w)");
    sregex_iterator it(S.begin(), S.end(), rx);
    sregex_iterator end;
    while (it != end) {
        if (it->str().size() < min_size)
            min_size = it->str().size();
        it++;
    }

    if (min_size == NOT_FOUND)
        return -1;
    return min_size;
}