#include "bits/stdc++.h"
#include <gmp.h>

using namespace std;

#if defined(_WIN32)
extern "C" {
	void* __stdcall LoadLibraryA(const char *name);
	void* __stdcall GetProcAddress(void *handle, const char *name);
}
struct DynamicLibrary {
	DynamicLibrary(const char *name) { _handle = LoadLibraryA(name); }
	void *get(const char *name) const { void *p = GetProcAddress(_handle, name); if(!p) cerr << "can't find: " << name << endl, abort(); return p; }
	void *_handle;
} gmp("mpir.dll");
#else
extern "C" {
	void* __libc_dlopen_mode(const char *x, int y);
	void* __libc_dlsym(void *x, const char *y);
}
struct DynamicLibrary {
	DynamicLibrary(const char *name) { _handle = __libc_dlopen_mode(name, 2); }
	void *get(const char *name) const { void *p = __libc_dlsym(_handle, name); if(!p) cerr << "can't find: " << name << endl, abort(); return p; }
	void *_handle;
} gmp("/usr/lib64/libgmp.so.10");	//yukicoder
#endif

#define EXPAND_MACRO_TO_STR_2(a) #a
#define EXPAND_MACRO_TO_STR(a) EXPAND_MACRO_TO_STR_2(a)
#define D(name) const auto my_##name = (decltype(::name)*)gmp.get(EXPAND_MACRO_TO_STR(name))
D(mpz_init_set_str);
D(mpz_popcount);

#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	//  \sum_n (2^(n+1)-1) N[n]
	//= 2 N - popcnt(N)
	string N;
	while(cin >> N) {
		mpz_t z;
		my_mpz_init_set_str(z, N.c_str(), 10);
		int ans = (int)my_mpz_popcount(z);
		printf("%d\n", ans);
	}
	return 0;
}