import java.util.Scanner;

public class test {
    static int s = 0;

    public static void f(int n) {
        if (n > 0) {
            if ((n % 10) % 2 == 0) {
                s++;
            }
            f(n / 2);
        }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        f(n);
        System.out.print(s);
    }
}