poj 1503 大数相加(java)

import java.math.*;
import java.util.Scanner;

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