Problem solve using java

Digital Roots

Department of Mathematics, University of Peradeniya needs a computer program to compute Digital roots. Digital roots are defined as a positive integer is found by summing the digits of the integer. If the resulting value is a single digit then that digit is the digital root. If the resulting value contains two or more digits, those digits are summed and the process is repeated. This is continued as long as necessary to obtain a single digit. More information can be found here
 (http://en.wikipedia.org/wiki/Digital_root).

For example, consider the positive integer 24. Adding the 2 and the 4 yields a value of 6. Since 6 is a single digit, 6 is the digital root of 24. Now consider the positive integer 39. Adding the 3 and the 9 yields 12. Since 12 is not a single digit, the process must be repeated. Adding the 1 and the 2 yields 3, a single digit and also the digital root of
39.

Input


The input n (1<=n<=9999999999999999999999999999999999999999999999999999999999999999999999999999999) contains a positive integer for which the digital root must be calculated.

Output
Output the digital root of the input.

Sample Input                                   Output

24                                                       6

3                                                         3

39                                                       3




ANSWER



import java.math.BigInteger;
import java.util.Scanner;

public class Qc {
    public static void main(String []args){
        Scanner sc = new Scanner(System.in);
        String in = sc.nextLine();
        BigInteger input2 = new BigInteger(in);
         BigInteger stat = new BigInteger("10");
     
        int mod=0;
     
        while(input2.compareTo(stat)==1 || input2.compareTo(stat)==0
            ){
            mod+=input2.remainder(stat).intValue();
            input2=input2.divide(stat);
         
           if(input2.longValue()<=10){
               BigInteger temp=input2;
                input2=new BigInteger(Integer.toString(mod));
                input2=input2.add(temp);
           
                mod=0;
            }
        }
        System.out.print(input2);
     
     
     
    }
}