#include<iostream>
#include<string>
#include<regex>
using namespace std;

int main()
{
	string s;
	regex regex("c.*w.*w");
	smatch match;
	int min = 100;
	cin >> s;
	if (regex_search(s, match, regex) == false) {
		cout << -1 << endl;
		return 0;
	}
	for (size_t i = 0; i < match.size(); ++i) {
		if (match.length(i) < min) {
			min = match.length(i);
		}
	}
	cout << min << endl;
	return 0;
}