#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

#include <sstream>
#include <algorithm>
#include <cmath>

#include <string>
#include <cstring>
#include <vector>
#include <valarray>
#include <array>

#include <queue>
#include <complex>
#include <set>
#include <map>
#include <stack>
#include <list>

#include<cassert>//assert();
#include <fstream>
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
#ifdef getchar_unlocked
#define mygc(c) (c)=getchar_unlocked()
#else
#define mygc(c) (c)=getchar()
#endif
#ifdef putchar_unlocked
#define mypc(c) putchar_unlocked(c)
#else
#define mypc(c) putchar(c)
#endif
/////////
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
/////////
using namespace::std;
/////////
#ifdef _DEBUG
#define DEBUG_BOOL(b) assert(b)
#else
#define DEBUG_BOOL(b) 
#endif
/////////
//#define MY_TIME_COUNT 1
#ifdef MY_TIME_COUNT
#include <windows.h>
#endif
/////数値読み込み
#define ENABLE_READER_ON(T)	\
inline void reader(T &x){\
	int k;x = 0;bool flag = true;\
	while(true){\
		mygc(k);\
		if( k == '-'){\
			flag = false;break;\
		}\
		if('0' <= k && k <= '9'){\
			x = k - '0';break;\
		}\
	}\
	if( flag ){\
		while(true){\
			mygc(k);\
			if( k<'0' || '9'<k)break;\
			x = x * 10 + (k - '0');\
		}\
	}else{\
		while(true){\
			mygc(k);\
			if( k<'0' || '9'<k)break;\
			x = x * 10 - (k-'0');\
		}\
	}\
}
//整数
ENABLE_READER_ON(int)
ENABLE_READER_ON(long)
ENABLE_READER_ON(long long)
ENABLE_READER_ON(unsigned int)
ENABLE_READER_ON(unsigned long)
ENABLE_READER_ON(unsigned long long)

//////
//文字読み込み
inline int reader(char c[]){int i,s=0;
for(;;){mygc(i);if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF) break;}
c[s++]=i;
for(;;){mygc(i);if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF) break;c[s++]=i;}
c[s]='\0';return s;
}

inline int reader(string& c,int size=100){int i;c.reserve(size);
for(;;){mygc(i);if(i != ' '&&i != '\n'&&i != '\r'&&i != '\t'&&i != EOF)break;}
c.push_back(i);
for(;;){mygc(i);if(i == ' ' || i == '\n' || i == '\r' || i == '\t' || i == EOF)break;c.push_back(i);}
return c.size();}

/////////
//数値出力
#define ENABLE_WRITER_ON(T)	\
inline void writer(T x){char f[20];int s = 0;\
if (x<0){mypc('-');while(x){f[s++] = ~(x%10)+1,x /= 10;}}\
else{while(x){f[s++] = (x % 10), x /= 10;}}\
if (!s)f[s++] = 0;while (s--)mypc(f[s] + '0');}

ENABLE_WRITER_ON(int)
ENABLE_WRITER_ON(long)
ENABLE_WRITER_ON(long long)
ENABLE_WRITER_ON(unsigned int)
ENABLE_WRITER_ON(unsigned long)
ENABLE_WRITER_ON(unsigned long long)
/////////
inline void writer(const char c[]){for (int i = 0; c[i] != '\0'; i++)mypc(c[i]); }
inline void writer(const string str){writer( str.c_str() );}
/////////
/**/
int popcount(ULL N){//64
	N -=  (N >> 1) & 0x5555555555555555ULL;
	N  = ((N >> 2) & 0x3333333333333333ULL) + (N & 0x3333333333333333ULL);
	N  = ((N >> 4) + N) & 0x0F0F0F0F0F0F0F0FULL;
	return (int)( (N * 0x0101010101010101ULL) >> 56);
}

#define ketaMax		19
#define BASE_MAX	(ULL)0xFFFFFFFFFFFFFFFF
#define FIVE_POW_19	(unsigned long long)19073486328125
#define MASK16_00	(unsigned long long)0x000000000000FFFF
#define MASK16_01	(unsigned long long)0x00000000FFFF0000
#define MASK16_02	(unsigned long long)0x0000FFFF00000000
struct bigNum{
public:
	int NumSize;//確保しているindex+1
	int TopIndex;//値の入っているindex+1
	vector<unsigned long long> Num;//10^6
	
	bigNum(){
		NumSize = 1;
		TopIndex = 1;
		Num.reserve(65536);//Num.reserve(51906);
	}
	int setFromString(const string& str);
};

int Count(const vector<unsigned long long>& Num,const int NumSize){
	int ret = 0;
	for(int i=0;i<NumSize;++i){
		ret += popcount(Num[i]);
	}
	return ret;
}

int bigNum::setFromString(const string& str){
	//Numの初期化をする。
	int len = str.size();
	NumSize = (int)(len*0.05190512648) + 1;

	Num = vector<unsigned long long>(NumSize,0);
	TopIndex = 1;//0の値が[0]に入っている

	int Q = 1 + (len-1)%ketaMax;
	unsigned long long firstNum = 0;

	int NumPos = 0;
	int strPos = 0;
	for(strPos = 0;strPos<Q;++strPos){
		firstNum = firstNum*10 + str[strPos] - '0';
	}
	//this->add(calNum);
	this->Num[0] = firstNum;//最初の値。

	unsigned long long CAL1,CAL2,CARR,CARR_UP;
	/////////////mul
	vector<unsigned long long> org;
	unsigned long long ter;
	
	unsigned long long calNum[4];
	/////////////
	CARR_UP = 0;
	while( strPos < len ){
		for(int i=0;i<ketaMax;++i){
			CARR_UP = CARR_UP*10 + str[strPos++] - '0';
		}
		//mul
		//*10^19
		DEBUG_BOOL( ((ULL)10000000000000000000) < BASE_MAX);//10^19
		//値の保存
		org = this->Num;
		const int orgTopIndex = this->TopIndex;
	
		//値が入っている部分だけ0初期化
		for(int i=0; i<orgTopIndex; ++i){
			this->Num[i] = 0;
		}

		//unsigned long long CAL1=0;
		//unsigned long long CAL2=0;
		CARR=0;
		int i;
		for(i=0; i<orgTopIndex; ++i){
			//ter = org.Num[i];
			ter = org[i];
			calNum[0] = ((ter & MASK16_00)) * FIVE_POW_19;
			calNum[1] = ((ter & MASK16_01)>>16) * FIVE_POW_19;
			calNum[2] = ((ter & MASK16_02)>>32) * FIVE_POW_19;
			calNum[3] = (ter>>48) * FIVE_POW_19;

			CAL1 = this->Num[i];//値を持ってくる。
			CAL2 = CAL1;//保存しておく
			CARR = CAL2 > (CAL1 += (CARR_UP));//下からの繰上げ//CARRのリセット

			CAL2 = CAL1;
			CARR += CAL2 > (CAL1 += (calNum[0]<<19) );
			CAL2 = CAL1;
			CARR += CAL2 > (CAL1 += (calNum[1]<<35));
			CAL2 = CAL1;
			CARR += CAL2 > (CAL1 += (calNum[2]<<51));
			this->Num[i] = CAL1;//値を戻す。

			CARR_UP =( ( ( calNum[0]>>(64-19) ) + ( calNum[1]>>(64-35) ) ) +
				( ( calNum[2]>>(64-51) ) + (calNum[3]<<(3)) ) +
				CARR);
		}
	
		while( CARR_UP ){
			CAL1 = this->Num[i];//値を持ってくる。
			CAL2 = CAL1;//保存しておく
			CARR_UP = CAL2 > (CAL1 += (CARR_UP));
			this->Num[i++] = CAL1;//値を戻す。
		}
		if(i > this->TopIndex){
			this->TopIndex = i;
		}
		DEBUG_BOOL(CARR_UP == 0);
	}

	return NumSize;
}

inline void solve(){
	string str;
	reader(str);

	//char str[1000001];
	//fread(str,1,1000001,stdin);
//////////////////////////////
	
	bigNum bn;
	bn.setFromString(str);
	//cout << "TopIndex\t" << bn.TopIndex << endl;
	//cout << "NumSize\t" << bn.NumSize << endl;
	writer( Count(bn.Num,bn.TopIndex) );
	//mypc('\n');
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//小数を10進数表示
    //cout << setprecision(16);//小数をいっぱい表示する。16?
#ifdef MY_TIME_COUNT
	LARGE_INTEGER freq;
	QueryPerformanceFrequency(&freq);
	LARGE_INTEGER start, end;
	QueryPerformanceCounter(&start);
#endif
	solve();
#ifdef MY_TIME_COUNT
	QueryPerformanceCounter(&end);
	cout << (double)(end.QuadPart - start.QuadPart) / freq.QuadPart << "sec.\n";
#endif
	return 0;
}