#include<iostream>
#include<string>
using namespace std;
int main() {
	string S;
	int cwwFlag = false;

	int cwwCounter[2] = { 100,0 };

	cin >> S;
	for (int i = 0; i < S.length(); i++) {
		if (S[i] == 'c'&&cwwFlag == 0) {
			cwwFlag++;
		}
		if (cwwFlag > 0) {
			cwwCounter[1]++;
			if(S[i] == 'w') cwwFlag++;
			if (cwwFlag == 3) {
				if (cwwCounter[1] < cwwCounter[0]) {
					cwwCounter[0] = cwwCounter[1];
				}
				cwwCounter[1] = 0;
				cwwFlag = 0;
			}
		}
	}
	if (cwwCounter[0] == 100) cwwCounter[0] = -1;
	cout << cwwCounter[0] << endl;

	return 0;
}