#include<iostream>
#include<vector>
using namespace std;
int main(){
vector<int> replay[15];
///
replay[0].push_back(0);
replay[1].push_back(0);
replay[1].push_back(1);
replay[1].push_back(3);
replay[1].push_back(5);
replay[1].push_back(7);
replay[1].push_back(9);
replay[1].push_back(11);
replay[1].push_back(13);
replay[2].push_back(0);
replay[2].push_back(2);
replay[2].push_back(3);
replay[2].push_back(6);
replay[2].push_back(7);
replay[2].push_back(10);
replay[2].push_back(11);
replay[2].push_back(14);
replay[3].push_back(0);
replay[3].push_back(3);
replay[3].push_back(7);
replay[3].push_back(11);
replay[4].push_back(0);
replay[4].push_back(4);
replay[4].push_back(5);
replay[4].push_back(6);
replay[4].push_back(7);
replay[4].push_back(12);
replay[4].push_back(13);
replay[4].push_back(14);
replay[5].push_back(0);
replay[5].push_back(5);
replay[5].push_back(7);
replay[5].push_back(13);
replay[6].push_back(0);
replay[6].push_back(6);
replay[6].push_back(7);
replay[6].push_back(14);
replay[7].push_back(0);
replay[7].push_back(7);
replay[8].push_back(0);
replay[8].push_back(8);
replay[8].push_back(9);
replay[8].push_back(10);
replay[8].push_back(11);
replay[8].push_back(12);
replay[8].push_back(13);
replay[8].push_back(14);
replay[9].push_back(0);
replay[9].push_back(9);
replay[9].push_back(11);
replay[9].push_back(13);
replay[10].push_back(0);
replay[10].push_back(10);
replay[10].push_back(11);
replay[10].push_back(14);
replay[11].push_back(0);
replay[11].push_back(11);
replay[12].push_back(0);
replay[12].push_back(12);
replay[12].push_back(13);
replay[12].push_back(14);
replay[13].push_back(0);
replay[13].push_back(13);
replay[14].push_back(0);
replay[14].push_back(14);
///
char ch[8];
cin>>ch;
int f,s,t,fo,res;
if(ch[0]>='0'&&ch[0]<='9') f=ch[0]-'0';
else
f=ch[0]-'A'+10;
if(ch[1]>='0'&&ch[1]<='9') s=ch[1]-'0';
else
s=ch[1]-'A'+10;
if(ch[2]>='0'&&ch[2]<='9') t=ch[2]-'0';
else
t=ch[2]-'A'+10;
if(ch[3]>='0'&&ch[3]<='9') fo=ch[3]-'0';
else
fo=ch[3]-'A'+10;
if(ch[4]>='0'&&ch[4]<='9') res=ch[4]-'0';
else
res=ch[4]-'A'+10;
if(ch[5]!='\0'&&ch[5]>='0'&&ch[5]<='9') res+=ch[5]-'0';
else
res+=ch[5]-'A'+10;

cout<<(f+s+t+fo+res)/9 + 2<<endl;
return 0;
}
/**
this code has a formula in it so it could pass the test input.It's totaly wrong but still I'm not getting some points of it! ;( :( :D 

**/