UVA - 424 - Integer Inquiry

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);
        BigInteger sum=BigInteger.ZERO;
            while(true) {
               String str=br.readLine();
               BigInteger x=new BigInteger(str);
               if(x.compareTo(BigInteger.ZERO)==0)
                   break;
               sum=sum.add(x);
            }
            System.out.println(sum);
    }
}