# include <bits/stdc++.h>
using namespace std;
typedef long long ll; 
//# define int long long
# define lc u << 1
# define rc u << 1 | 1
# define fi first
# define se second
const int N = 1000005;

char s[N], t[N];
int a[N], b[N];
void solve ()
{
	int len = strlen(s);
	for (int i = 0; i < len; i ++ ) a[len - i - 1] = s[i] - '0';
	int k;
	for (k = 0; len; )
	{
		for (int i = len; i >= 1; i -- ) a[i - 1] += a[i] % 2 * 10, a[i] /= 2;
		b[k ++ ] = a[0] % 2; a[0] /= 2;
		while (len && !a[len - 1]) len -- ;
	}
	a[k] = 0;
	for (int i = 0; i < k; i ++ ) t[k - i - 1] = b[i] + '0'; 
}
signed main ()
{
//	freopen ("double.in", "r", stdin); freopen ("double.out", "w", stdout);
	scanf ("%s", s); 
	solve ();
	int len = strlen (t);
	ll ans = 0;
	for (int i = 0; i < len; i ++ ) ans += t[i] - '0';
	printf ("%lld\n", ans);
	return 0;
}