#include<iostream>

#include "cstdio"

using namespace std;

int main()

{

    int n;

    while(~scanf("%d",&n)&&n)

    {

        int sum=;

        while(true){

           while(n>){

                sum+=n%;

                n/=;

            }

            if(sum>)

            {

                 n=sum;sum=;

            }

            else{

                break;

            }

        }

        cout<<sum<<endl;

    }

    return ;

}

#include "iostream"

#include "cstdio"

#include "string"

using namespace std;

int main()

{

    string str;

    while(cin>>str&&str!="")

    {

        int len=str.length();

        int num=;

        for(int i=;i<len;i++){

            num+=str[i]-'';

            if(num>){num=num/+num%;}

        }

        cout<<num<<endl;

    }

    return ;

}