Use BufferedReader
, you can make it read from standard input like this:
BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
String line;
while ((line = stdin.readLine()) != null && line.length()!= 0) {
String[] input = line.split(" ");
if (input.length == 2) {
System.out.println(calculateAnswer(input[0], input[1]));
}
}