import java.util.Scanner;

public class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
String str = sc.nextLine();

    int sum = 0;
    for(char c : str.toCharArray())
        if(c >= '0' && c <= '9')
            sum += 1;
    System.out.println(sum);
}

}