//#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

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

#include <string>
//#include <vector>
//#include <valarray>

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

#include<cassert>//assert();
*/
#include <fstream>//ファイル操作
/////////
#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>
/////////
//#define mygc(c) (c)=getchar_unlocked()
/////////
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
/////////
using namespace::std;
/////////
int reader(char c[]){
	int i,s=0;
	for(;;){
		//mygc(i);
		//i = getchar_unlocked();
		i = getchar();
		if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF) break;
	}c[s++]=i;
	for(;;){
		//mygc(i);
		//i = getchar_unlocked();
		i = getchar();
		if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF) break;
		c[s++]=i;
	}c[s]='\0';return s;
}
/////////
#define ketaMax 9

ULL popcount(ULL b){
	b -=  (b >> 1) & 0x5555555555555555ULL;
	b  = ((b >> 2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
	b  = ((b >> 4) + b) & 0x0F0F0F0F0F0F0F0FULL;
	return (b * 0x0101010101010101ULL) >> 56;
}

int to_num(ULL* ans, string str){
	int len = str.length();
	string temp;
	ULL pow10 = 1;

	int pos = 0;
	ans[0] = 0;
	for(int i= 0;i<len;++i){
		if((len-i)%ketaMax == 0 && i != 0){
			++pos;
			ans[pos] = 0;
		}
		temp = str[i];
		ans[pos] = ans[pos]*10 +stoi( temp );
	}
	return pos+1;
}

struct vnum{
	ULL num[1000000/ketaMax + 1];

	int len;
	ULL powMax;
	ULL divNum;
	int divShift;
	void set(string str){
		powMax = 1;
		len = to_num(num, str);
		
		powMax		= (ULL)1000000000;
		divNum		= (ULL)4294967296;//(ULL)17179869184;//(ULL)536870912;
		divShift	= 32;//34;//29;
	}

	void div(){//
		ULL ans = 0;
		//ULL mask = divNum-1;
		ULL ama = 0;

		int start = 0;
		while( start < len ){
			ULL temp;
			ama = 0;
			long i;
			for(i=start; i < len-15;i+=16){//上の桁から
				temp	= num[i] + ama * 1000000000;//temp	= num[i] + ama * powMax;
				num[i]	= temp >> 32;	//商//num[i]	= temp >> divShift;	//商
				ama		= temp & 0xFFFFFFFF;//あまり

				temp	= num[i+1] + ama * 1000000000;
				num[i+1]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+2] + ama * 1000000000;
				num[i+2]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+3] + ama * 1000000000;
				num[i+3]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+4] + ama * 1000000000;
				num[i+4]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+5] + ama * 1000000000;
				num[i+5]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+6] + ama * 1000000000;
				num[i+6]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+7] + ama * 1000000000;
				num[i+7]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+8] + ama * 1000000000;
				num[i+8]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+9] + ama * 1000000000;
				num[i+9]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+10] + ama * 1000000000;
				num[i+10]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+11] + ama * 1000000000;
				num[i+11]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+12] + ama * 1000000000;
				num[i+12]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+13] + ama * 1000000000;
				num[i+13]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+14] + ama * 1000000000;
				num[i+14]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;

				temp	= num[i+15] + ama * 1000000000;
				num[i+15]= temp >> 32;
				ama		= temp & 0xFFFFFFFF;
			}
			for( ;i < len;i++){
				temp	= num[i] + ama * 1000000000;
				num[i]	= temp >> 32;
				ama		= temp & 0xFFFFFFFF;
			}
			ans += popcount(ama);
			
			//if( num[start] == 0 ){++start;}
			start += (num[start] == 0);
			start += (num[start] == 0);
			start += (num[start] == 0);
			start += (num[start] == 0);
		}
		cout << ans << endl;
	}
};

//string str(1000000,'0');
char str[1000002];
vnum Num;
void solve(){	
	//str.reserve(1000000);
	reader(str);
	//cin >> str;

	Num.set(str);
	Num.div();
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	solve();
	
	return 0;
}