public void doBtnBrowsePressed(ActionEvent event) {
        FileChooser fileChooser = new FileChooser();
        FileChooser.ExtensionFilter extFilter = new FileChooser.ExtensionFilter("Booking file (*.csv)", "*.csv");
        fileChooser.getExtensionFilters().add(extFilter);

        File file = fileChooser.showOpenDialog(null);

        if (file != null) {
            Problem problem = readProblem(file.getPath());
            showProblem(problem);
        }
    }