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

int main()
{
	string s;
	regex regex("c[^w]*w[^w]*w");
	smatch match;
	int min = 100;
	cin >> s;
	sregex_token_iterator first(begin(s),end(s), regex);
	sregex_token_iterator last;
	if (first == last) {
		cout << -1 << endl;
		return 0;
	}
	while (first != last) {
		if (first->length() < min) {
			min = first->length();
		}
		++first;
	}
	cout << min << endl;
	return 0;
}