What will be the output of the following Java program?

class output

$\{$

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

$\{$

String x $=$ "Hello";

String y $=$ x$.$replace$(\text{'}\text{'},\text{'}$w$\text{'})$;

System.out.println$($y$)$;

$\}$

$\}$

$(2$ Puan$)$

$12$

$31$

$13$

$23$