import java.io.*;
import java.util.*;
public class Main
{
  public static void main (String[] args)
  {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
}
} import java.io.*; io.* java import java.util.*; util.* java public class Main
{
  public static void main (String[] args)
  {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
}
} Main public static void main (String[] args)
  {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
} main {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
} int count =0; count 0 Scanner reader = new Scanner(System.in); reader new Scanner(System.in) int a=reader.nextInt(); a reader.nextInt() reader.nextInt reader for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  } int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
if(a%2==1)
count++;
  a=a/10;
  } {
if(a%2==1)
count++;
  a=a/10;
  } if(a%2==1)
count++; a%2==1 a%2 a 2 1 count++ count a=a/10 a a/10 a 10 System.out.print(count) System.out.print System.out System System.out count String[] args args public class Main
{
  public static void main (String[] args)
  {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
}
} public class Main
{
  public static void main (String[] args)
  {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
}
} Main
import java.io.*;
import java.util.*;
public class Main
{
  public static void main (String[] args)
  {
    int count =0;
    Scanner reader = new Scanner(System.in);
    int a=reader.nextInt();
for(int i=0;i<3;i++){
if(a%2==1)
count++;
  a=a/10;
  }
  System.out.print(count);
}
}