What will code output? abstract class P $\{$

public abstract int calculate$($int x$)$;

$\}$

class Q extends P $\{$

public int calculate$($int x$)\{$

return x $+1$;

$\}$

$\}$

class R extends Q $\{$

public int calculate$($int x$)\{$

return super.calculate$($x$)*2$;

$\}$

$\}$

public class Test $\{$

public static void main$($String$[]$ args$)\{$

P obj $=$ new R$()$;

System.out.println$($obj$.$calculate$(4))$;

$\}$

$\}$