UVA - 10922 - 2 the 9s

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class Main {

    public static void main(String[] args) throws IOException {
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(isr);
        StringBuffer sb = new StringBuffer("");
        String m = "";
        while(true) {
            m=br.readLine();
            if("0".equals(m))
                break;
           BigInteger x=new BigInteger(m);
           if(x.remainder(BigInteger.valueOf(9)).compareTo(BigInteger.ZERO)==0){
               sb.append(m).append(" is a multiple of 9 and has 9-degree ").append(sum(m,true)).append(".\n");
           }else{
               sb.append(m).append(" is not a multiple of 9.\n");
           }
        }
        System.out.print(sb);
    }
   
    static int sum (String x,boolean flag){
        if("9".equals(x)&&flag)
            return 1;
        if("9".equals(x)&&!flag)
            return 0;
        int count=0;
        for(int i=0;i<x.length();i++){
            count+=x.charAt(i)-'0';
        }
        return 1+sum(count+"",false);
    }
}