#include"bits/stdc++.h"
using namespace std;
int main() {
	string s; cin >> s;
	int a = 0; int ans = s.length() + 1;
	int k;
	for (int i = 0; i < s.length(); i++) {
		if (s[i] == 'c') {
			k = i - 1; a = 1;
		}
		else if (s[i] == 'w'&&a == 1) {
			a = 2;
		}
		else if (s[i] == 'w'&&a == 2) {
			ans = min(ans, i - k);
		}
	}
	if (ans != s.length() + 1) {
		cout << ans << endl;
	}
	else {
		cout << -1 << endl;
	}
}