import java.util.HashMap;
import java.util.Scanner;

public class Main2 {
    public static void main(String[] args) {
        //String s = new Scanner(System.in).nextLine();
        String s = "bcbcobc";
        int count = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'o') {
                count++;
            }
        }
        if (count % 2 == 0) {
            System.out.println(s.length());
        } else {
            System.out.println(s.length() - 1);
        }
    }
}