1 #include
      
        2 #include
       
         3 #include
        
          4 int main() 5 { 6     char s[10000]; 7     int i,num,b; 8     while(scanf("%s",s)!=-1) 9     {10         b=atoi(s);11         if(b==0)12             break;13         num=0;14         for(i=0;s[i]!='\0';i++)15         16             num=(num+(s[i]-'0'))%9;17         if(num>0)18             printf("%d\n",num);19         else20             printf("9\n");21     }22     return 0;23 }