import java.util.*;

public class main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        char[] chars = s.toCharArray();
        int charlonger = s.length();
        int i=0;
        int flag =0;
        int a=0,b=9999;
        int con=1;


        for(;i<charlonger;i++){
            if(chars[i] == 'c'){
                flag = 1;
                a=i;
            }else if(flag == 1 && chars[i] == 'w'){
                  flag = 2;

            }else if(flag == 2 && chars[i] == 'w' ){
                con ++;
                flag=0;
                if(i-a+1 <b){
                    b= i-a+1;
                }

            }
        }
        if(con >0){

            System.out.println(b);
        }else{
            System.out.println("-1");
        }
    }
}