Codeforces 376A Lever program in java

Lever.java

import java.math.BigInteger;
import java.util.Scanner;
public class Lever
{
    public static void main(String[] args)
    {
        Scanner z=new Scanner(System.in);
        String[] xx=z.next().split("\\^");
        StringBuilder sb=new StringBuilder(xx[0]);
        xx[0]= sb.reverse().toString();
        BigInteger a1=BigInteger.valueOf(0);
        BigInteger a2=BigInteger.valueOf(0);
        BigInteger a3=BigInteger.valueOf(0);
        for(int i=0;i<xx[1].length();i++){
            a1=a3;
            if(Character.getNumericValue(xx[1].charAt(i))>0){
                a2=BigInteger.valueOf(Character.getNumericValue(xx[1].charAt(i))*(i+1));
                a3=a1.add(a2);
            }
        }
        BigInteger b1=BigInteger.valueOf(0);
        BigInteger b2=BigInteger.valueOf(0);
        BigInteger b3=BigInteger.valueOf(0);
        for(int i=0;i<xx[0].length();i++){
            b1=b3;
            if(Character.getNumericValue(xx[0].charAt(i))>0){
                b2=BigInteger.valueOf(Character.getNumericValue(xx[0].charAt(i))*(i+1));
                b3=b1.add(b2);
            }
        }
        if(a3.compareTo(b3)==0)
            System.out.println("balance");
        else if(a3.compareTo(b3)==1)
            System.out.println("right");
        else
            System.out.println("left");
        z.close();
    }
}