#include <bits/stdc++.h>
using namespace std;

int main() {
	string s;
	cin >> s;

	vector<int> v(34, 101);
	int c = 0;
	bool b = 0;
	for (int i = 0; i < s.size(); i++) {
		if (s.at(i) == 'c') {
			int c = 0;
			for (int j = i; j < s.size(); j++) {
				char ch = s.at(j);
				if (ch == 'w') {
					c++;
				}

				if (c == 2) {
					v.push_back(j-i+1);
					b = 1;
					break;
				}
			}
		}
		else {
			continue;
		}
	}
	/*for (int i = 0; i < v.size(); i++) {
		cout << v.at(i) << endl;
	}*/

	sort(v.begin(), v.end());
	int a = v.at(0);

	if (!b) {
		cout << -1 << endl;
	}
	else {
		cout << a << endl;
	}
}