My 2 cents in Java:

public static void main(String[] args) throws IOException { BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

    try {
        String S = bufferedReader.readLine();
        System.out.println(Integer.parseInt(S));
    } catch (NumberFormatException e) {
        System.out.println("Bad String");
    }

    bufferedReader.close();
}