> #include<iostream>
> #include<string>
> using namespace std;
> 
> int main(){
>     
>    string str;
>    cin>>str;   
>    
>    while(str!="0"){
>         int i = str.size();
>         int j(0);
>         
>         for(int k=0;k<i;k++){
>                  j =  (j*10 + (str[k]-'0'))%9;       
>         }
>         
>         cout<<j<<endl;
>         cin>>str;
>    }
>    return 0;
> }