first assignment

@leapfrog-dipendra  @bhuwang  @anishmanandhar  @adhpawal  @Satish-Gupta  @Msanjib  @nerisa  @utsabneupane 
What are the reason behind using diffrent approach while decaring Scanner ,

YOu have used `private static Scanner scan;` here and `private static final Scanner SCANNER = new Scanner(System.in);` elsewhere ..