import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
		int length = (str.length() + 8) / 9;
		int[] arr = new int[length];
		for (int i = 0; i < length; i++) {
		    if (i == length - 1) {
		        arr[length - i - 1] = Integer.parseInt(str.substring(0, str.length() - i * 9));
		    } else {
		        arr[length - i - 1] = Integer.parseInt(str.substring(str.length() - (i + 1) * 9, str.length() - i * 9));
		    }
		}
		int start = 0;
		int mod = 0;
		while (start < length) {
		    int next = 0;
		    for (int i = start; i < length; i++) {
		        arr[i] += next * 1000000000;
		        next = arr[i] % 2;
		        arr[i] /= 2;
		        if (start == i && arr[i] == 0) {
		            start++;
		        }
		    }
		    mod += next;
		}
	    System.out.println(mod);
	}
}