UVA Problem ID 355 (The Bases Are Loaded)

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
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String input;
		StringBuilder sb=new StringBuilder(1000);
		
		while((input=br.readLine())!=null)
		{
			String numbers[]=input.trim().split(" +");
			try {
				BigInteger no=new BigInteger(numbers[2],Integer.parseInt(numbers[0]));
				String ans=no.toString(Integer.parseInt(numbers[1]));
				sb.append(numbers[2]+" base "+numbers[0]+" = "+(ans.toUpperCase())+" base "+numbers[1]);
			} catch (Exception e) {
				sb.append(numbers[2]+" is an illegal base "+numbers[0]+" number");
			}	
			sb.append("\n");
		}
		System.out.print(sb);
	}
}