import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	} main {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc int i = Integer.parseInt(s); i Integer.parseInt(s) Integer.parseInt Integer s int n = 0; n 0 for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		} int j = 1; int j = 1; j 1 j <= 100 j 100 j = 10 * j j = 10 * j j 10 * j 10 j {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		} {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		} if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			} (i / j) % 2 == 0 (i / j) % 2 (i / j) i j 2 0 { 
				
			} {
				n++;
			} n++ n System.out.println(n) System.out.println System.out System System.out n String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		int i = Integer.parseInt(s);
		int n = 0;
		for(int j = 1; j <= 100;j = 10 * j) {
			if((i / j) % 2 == 0) { 
				
			}else {
				n++;
			}
		}
		System.out.println(n);
	}
}