#include <iostream>
#include <cstring>
using namespace std;

int main() {
	string s;
	cin>>s;
	int ans=100;
	int S=s.size(),w1=S,w2=S;
	for(int i=S-1;i>=0;i--){
		if(s[i]=='w'){
			w1=w2;
			w2=i;
		}
		if(s[i]=='c'&&w1!=S){
			ans=min(ans,w1-i+1);
		}
	}
	if(ans==100)cout<<-1<<endl;
	else cout<<ans<<endl;
	return 0;
}