Java tips

import java.util.*;
import java.*;
import java.math.*;
public class Main {
    public static  BigInteger xx(BigInteger y) {    
        return y.multiply(BigInteger.valueOf(3));
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner cin = new Scanner(System.in);
        int t = cin.nextInt();
        int k,top;
        for (int tt=0;tt<t;++tt){
            k = cin.nextInt ();
            top = cin.nextInt();
            String s = cin.nextLine();
             char [] ss=s.toCharArray(); // string modifying a single character first converts it into a char array 
            ss[0] = '0' ;
            s = ss.toString(); // turn back to 
            BigDecimal x = new BigDecimal(ss);
             // s.charAt(0) = '0';
             // System.out.println(k+" "+ss+" " +top); 
            System.out.println(x);
            System.out.println(xx(BigInteger.valueOf(3)));
        }
    }

}