#include<iostream>
#include<string>
#include<algorithm>
#include<vector>

using namespace std;

//cがn回目に出てきたインデックスを返す。出てこなかった場合は-1を返す。
int find_c(string s, int n) {
	int cnt = 1;
	for (int i = 0; i < s.size(); i++) {
		if (s[i] == 'c') {
			if (cnt == n) {
				return i;
			}
			else {
				cnt++;
			}
		}
	}
	return -1;
}

//wがn番目に出てきたインデックス
int find_w(string s, int n) {
	int cnt = 1;
	for (int i = 0; i < s.size(); i++) {
		if (s[i] == 'w') {
			if (cnt == n) {
				return i;
			}
			else {
				cnt++;
			}
		}
	}
	return -1;
}
int main() {
	string s;
	cin >> s;
	vector<int> c_its, w_its;
	for (int i = 1; i < 99999999; i++) {
		int a = find_c(s, i);
		if (a == -1) break;
		else c_its.push_back(a);
	}
	for (int i = 1; i < 99999999; i++) {
		int a = find_w(s, i);
		if (a == -1) break;
		else w_its.push_back(a);
	}

	if (w_its.size() == 0) { cout << -1 << endl; return 0;}

	vector<int> answers;
	for (int i = 0; i < c_its.size(); i++) {
		for (int j = 0; j < w_its.size() - 1; j++) {
			if (w_its[j] - c_its[i] > 0 && w_its[j + 1] - c_its[i]) {
				answers.push_back(w_its[j + 1] - c_its[i]);
				break;
			}
		}
	}

	sort(answers.begin(), answers.end());
	if (!answers.empty()) cout << answers[0] + 1 << endl;
	else cout << -1 << endl;

}