UVa Problem ID 10921 (Find the Telephone)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException 
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String input;
        StringBuffer sb=new StringBuffer("");
       
        while((input=br.readLine())!=null)
        {
		if(input.length()<1 ||input.length()>30)
        		break;
        	for (int i = 0; i < input.length(); i++) 
        	{
				switch (input.charAt(i)) 
				{
					case '1':
					case '-':
					case '0':
					{
						sb.append(input.charAt(i));
						break;
					}
					case 'A':
					case 'B':
					case 'C':
					{
						sb.append(2);
						break;
					}
					case 'D':
					case 'E':
					case 'F':
					{
						sb.append(3);
						break;
					}
					case 'G':
					case 'H':
					case 'I':
					{
						sb.append(4);
						break;
					}
					case 'J':
					case 'K':
					case 'L':
					{
						sb.append(5);
						break;
					}
					case 'M':
					case 'N':
					case 'O':
					{
						sb.append(6);
						break;
					}
					case 'P':
					case 'Q':
					case 'R':
					case 'S':
					{
						sb.append(7);
						break;
					}
					case 'T':
					case 'U':
					case 'V':
					{
						sb.append(8);
						break;
					}
					case 'W':
					case 'X':
					case 'Y':
					case 'Z':
					{
						sb.append(9);
						break;
					}
				}
			}
        	sb.append("\n");
        }
        System.out.print(sb);
    }
}