import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    } main {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String[] str = sc.next().split(""); str sc.next().split("") sc.next().split sc.next() sc.next sc "" Map<String, Integer> map = new HashMap<>(); map new HashMap<>() for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        } String s str {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        } {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        } if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            } map.containsKey(s) map.containsKey map s {
                map.put(s, map.get(s)+1);
            } map.put(s, map.get(s)+1) map.put map s map.get(s)+1 map.get(s) map.get map s 1 {
                map.put(s, 1);
            } map.put(s, 1) map.put map s 1 System.out.println(map.containsKey("1") ? map.get("1") : 0) System.out.println System.out System System.out map.containsKey("1") ? map.get("1") : 0 map.containsKey("1") map.containsKey map "1" map.get("1") map.get map "1" 0 String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[] str = sc.next().split("");
        
        Map<String, Integer> map = new HashMap<>();
        for (String s : str) {
            if (map.containsKey(s)) {
                map.put(s, map.get(s)+1);
            } else {
                map.put(s, 1);
            }
        }
        
        System.out.println(map.containsKey("1") ? map.get("1") : 0);
    }
}
