#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <fstream>
#include <set>
#include <utility>
#include <algorithm>

using namespace std;

int max(int x, int y) {
	int a;
	(x > y) ? a = x : a = y;
	return a;
}

int min(int x, int y) {
	int a;
	(x < y) ? a = x : a = y;
	return a;
}

int main() {
	string s;
	getline(cin, s);
	int judge = 0, count = 0;
	bool ans = true;

	for (int i = 0; i < s.length(); i++) {
		if (judge > 0) count++;
		if (s[i] == 'c')judge ++;
		else {
			if (judge == 1) {
				if (s[i] == 'w') judge++;
			}
			else if (judge == 2) {
				if (s[i] == 'w') {
					cout << count+1 << endl;
					ans = false;
					break;
				}
			}
		}
	}
	if (ans)cout << -1 << endl;
	

	return 0;
}