import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	}

} Main public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	} main {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String string = scanner.next(); string scanner.next() scanner.next scanner string = string.replaceAll("0", "") string string.replaceAll("0", "") string.replaceAll string "0" "" System.out.println(string.length()) System.out.println System.out System System.out string.length() string.length string scanner.close() scanner.close scanner String[] args args public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	}

} public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		String string = scanner.next();

		string = string.replaceAll("0", "");

		System.out.println(string.length());

		scanner.close();
	}

}
