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;
        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");
        }
        if(min==Integer.MAX_VALUE){
            System.out.println(-1);
        }else{
            System.out.println(min);
        }
    }
}