import java.util.*;
import java.util.regex.*;

public class Main {
    public static void main(String[] args) throws Exception {
        var sc = new Scanner(System.in);
        
        String line = sc.next();
        
        var pattern = Pattern.compile("c.*?w.*?w");
        var matcher = pattern.matcher(line);
        
        int min = Integer.MAX_VALUE;
        
        while(matcher.find()){
            //System.out.println(matcher.group());
            min = Math.min(min, matcher.group().length());
        }
        
        if(min == Integer.MAX_VALUE){
            System.out.println(-1);
        }else{
            System.out.println(min);
        }
        
    }
}