import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        int a = S.indexOf("c");
        int min = Integer.MAX_VALUE;
        if(a==-1){
            System.out.println(-1);
        }else{
            while(a!=-1){
                S = S.substring(a+1);
                int b = S.indexOf("w");
                String t = S.substring(b+1);
                int c = t.indexOf("w");
                if(c!=-1 && min>b+c+3){
                    min = b+c+3;
                }
                a = S.indexOf("c");
            }
            System.out.println(min);
        }
    }
}