#include <iostream>
using namespace std;
 
int main(){
	string S;
	cin >> S;
	int now = 0;
	int start;
	for(int i = 0; i < S.size(); i++){
		if(S[i] == 'c' && !now){
			now++;
			start = i;
		}else if(S[i] == 'w' && now){
			now++;
		}
		if(now == 3){
			cout << i - start + 1 << endl;
			return 0;
		}
	}
	cout << -1 << endl;
}