UVA 424 - Integer Inquiry

package mypkg;

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

class Main {
 public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        BigInteger a,sum=BigInteger.ZERO;
        while(in.hasNext())
        {
            a=in.nextBigInteger();
            if(a.compareTo(BigInteger.valueOf(0))==0)
            break;
            sum=sum.add(a);
        }
        System.out.println(sum);
    }

}